Nos publications
Riikonen, Joakim; Rantanen, Jimi; Thapa, Rinez; Le, Nguyen T; Rigolet, Severinne; Fioux, Philippe; Turhanen, Petri; Bodiford, Nelli K; Kalluri, Jhansi R; Ikonen, Timo; Nissinen, Tuomo; Lebeau, Benedicte; Vepsalainen, Jouko; Coffer, Jeffery L; Lehto, Vesa-Pekka Rapid synthesis of nanostructured porous silicon carbide from biogenic silica Article de journal Journal of the American Ceramic Society, 104 (2), p. 766–775, 2021. @article{Riikonen2021, title = {Rapid synthesis of nanostructured porous silicon carbide from biogenic silica}, author = { Joakim Riikonen and Jimi Rantanen and Rinez Thapa and Nguyen T. Le and Severinne Rigolet and Philippe Fioux and Petri Turhanen and Nelli K. Bodiford and Jhansi R. Kalluri and Timo Ikonen and Tuomo Nissinen and Benedicte Lebeau and Jouko Vepsalainen and Jeffery L. Coffer and Vesa-Pekka Lehto}, doi = {10.1111/jace.17519}, year = {2021}, date = {2021-02-01}, journal = {Journal of the American Ceramic Society}, volume = {104}, number = {2}, pages = {766--775}, abstract = {Nanostructured silicon carbide (SiC) is an exceptional material with numerous applications, for example, in catalysis, biomedicine, high-performance composites, and sensing. In this study, a fast and scalable method of producing nanostructured SiC from plant materials by magnesiothermic reduction via self-propagating high-temperature synthesis (SHS) route was developed. The produced biogenic material possessed a high surface area above 200 m(2)/g with a SiC crystallite size below 10 nm, which has not been done previously by SHS. This method enables affordable synthesis of the material plant-based precursors in a reaction that only takes a few seconds, thereby paving a way for nanostructured SiC production in high volumes using renewable resources. The material was also functionalized with carboxylic acid and bisphosphonate moieties, and its use as metal adsorbent in applications such as wastewater remediation was demonstrated.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Nanostructured silicon carbide (SiC) is an exceptional material with numerous applications, for example, in catalysis, biomedicine, high-performance composites, and sensing. In this study, a fast and scalable method of producing nanostructured SiC from plant materials by magnesiothermic reduction via self-propagating high-temperature synthesis (SHS) route was developed. The produced biogenic material possessed a high surface area above 200 m(2)/g with a SiC crystallite size below 10 nm, which has not been done previously by SHS. This method enables affordable synthesis of the material plant-based precursors in a reaction that only takes a few seconds, thereby paving a way for nanostructured SiC production in high volumes using renewable resources. The material was also functionalized with carboxylic acid and bisphosphonate moieties, and its use as metal adsorbent in applications such as wastewater remediation was demonstrated. |
Schobing, Julie; Cesario, Moises; Dorge, Sophie; Nouali, Habiba; Patarin, Joel; Martens, Johan; Brilhac, Jean-Francois CuO supported on COK-12 and SBA-15 ordered mesoporous materials for temperature swing SOx adsorption Article de journal Fuel Processing Technology, 211 , p. 106586, 2021. @article{Schobing2021, title = {CuO supported on COK-12 and SBA-15 ordered mesoporous materials for temperature swing SOx adsorption}, author = { Julie Schobing and Moises Cesario and Sophie Dorge and Habiba Nouali and Joel Patarin and Johan Martens and Jean-Francois Brilhac}, doi = {10.1016/j.fuproc.2020.106586}, year = {2021}, date = {2021-01-01}, journal = {Fuel Processing Technology}, volume = {211}, pages = {106586}, abstract = {Ordered mesoporous SBA-15 and COK-12 supports with similar mesopore diameter were loaded with 15 wt% of CuO and evaluated as adsorbents in a desulfurization process involving SOx adsorption and regeneration. Both SBA-15 and COK-12 have a hexagonal arrangement of parallel tubular mesopores. The impact of relatively small differences of the structural and textural properties of the two supports on SOx adsorption and regenerability is investigated. After impregnation with copper nitrate solution and calcination at 500 degrees C, the samples do not show any characteristic XRD pattern of copper-based phases, confirming the highly dispersed state of CuO, which is also checked by Transmission Electron Microscopy (TEM). The COK-CuO15 sample has slightly higher porosity than the SBA-CuO15 sample. The pore volume of both supports is slightly reduced after impregnation-calcination and shaping (Pelletized, Crushed and Sieved - PCS) steps. As for its SOx adsorptive properties, after fifteen adsorption-regeneration cycles at 400 degrees C, the COK-CuO15_PCS sample exhibits dynamic and total adsorption capacities higher than those of the SBA-CuO15_PCS adsorbent. In addition, both adsorbents preserve their adsorption capacities over the 15 cycles. The COK-12 support for the CuO active phase provides very promising results in comparison with the literature data for SBA-CuO15 adsorbent.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ordered mesoporous SBA-15 and COK-12 supports with similar mesopore diameter were loaded with 15 wt% of CuO and evaluated as adsorbents in a desulfurization process involving SOx adsorption and regeneration. Both SBA-15 and COK-12 have a hexagonal arrangement of parallel tubular mesopores. The impact of relatively small differences of the structural and textural properties of the two supports on SOx adsorption and regenerability is investigated. After impregnation with copper nitrate solution and calcination at 500 degrees C, the samples do not show any characteristic XRD pattern of copper-based phases, confirming the highly dispersed state of CuO, which is also checked by Transmission Electron Microscopy (TEM). The COK-CuO15 sample has slightly higher porosity than the SBA-CuO15 sample. The pore volume of both supports is slightly reduced after impregnation-calcination and shaping (Pelletized, Crushed and Sieved - PCS) steps. As for its SOx adsorptive properties, after fifteen adsorption-regeneration cycles at 400 degrees C, the COK-CuO15_PCS sample exhibits dynamic and total adsorption capacities higher than those of the SBA-CuO15_PCS adsorbent. In addition, both adsorbents preserve their adsorption capacities over the 15 cycles. The COK-12 support for the CuO active phase provides very promising results in comparison with the literature data for SBA-CuO15 adsorbent. |
Gencoglu, Turkan; Eren, Tugce Nur; Lalevee, Jacques; Avci, Duygu Photoinitiating systems based on poly(ethylene imine) for Michael addition and free radical photopolymerization Article de journal Journal of Photochemistry and Photobiology A-chemistry, 404 , p. 112959, 2021. @article{Gencoglu2021, title = {Photoinitiating systems based on poly(ethylene imine) for Michael addition and free radical photopolymerization}, author = { Turkan Gencoglu and Tugce Nur Eren and Jacques Lalevee and Duygu Avci}, doi = {10.1016/j.jphotochem.2020.112959}, year = {2021}, date = {2021-01-01}, journal = {Journal of Photochemistry and Photobiology A-chemistry}, volume = {404}, pages = {112959}, abstract = {Multifunctional polymeric photoinitiators with the ability of aza-Michael addition with acrylates, free radical polymerization of (meth)acrylates through type II photoinitiation and charge transfer complex (CTC) formation with iodonium salt (Iod) were prepared. They were synthesized via aza-Michael addition reaction between branched poly(ethylene imine) (PEI}, keywords = {}, pubstate = {published}, tppubtype = {article} } Multifunctional polymeric photoinitiators with the ability of aza-Michael addition with acrylates, free radical polymerization of (meth)acrylates through type II photoinitiation and charge transfer complex (CTC) formation with iodonium salt (Iod) were prepared. They were synthesized via aza-Michael addition reaction between branched poly(ethylene imine) (PEI |
Renkert, S; Fall, S; Motamen, S; Jarrosson, Th; Serein-Spirau, F; Heiser, Th; Simon, L; Reiter, G; Bubendorff, J L A new growth process for crystalline ultra-thin layers of conjugated oligomers used in field-effect transistor applications Article de journal Applied Surface Science, 539 , p. 148024, 2021. @article{Renkert2021, title = {A new growth process for crystalline ultra-thin layers of conjugated oligomers used in field-effect transistor applications}, author = { S. Renkert and S. Fall and S. Motamen and Th Jarrosson and F. Serein-Spirau and Th Heiser and L. Simon and G. Reiter and J. L. Bubendorff}, doi = {10.1016/j.apsusc.2020.148024}, year = {2021}, date = {2021-01-01}, journal = {Applied Surface Science}, volume = {539}, pages = {148024}, abstract = {Most organic semiconductor materials dewet on silicon wafers with thermal oxide layers. While Si-wafers represent convenient substrates for building a field effect transistor (FET), dewetting largely destroys the possibility for obtaining a compact and continuous crystalline thin organic semiconductor film and thus limits the mobility in these systems. Using oligothiophenes, we present an approach where the initial dewetting process can be turned into an advantage for generating very thin but large crystalline domains of a size up to the millimetres with all molecules sharing a single orientation. Our approach can be easily extended to other molecules, which have strongly differing growth velocities in the various directions of the crystal, for example due to directional pi-stacking interactions. FETs devices based on such large crystalline domains showed charge carrier mobilities that were two orders of magnitude higher compared to non-crystallized films.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Most organic semiconductor materials dewet on silicon wafers with thermal oxide layers. While Si-wafers represent convenient substrates for building a field effect transistor (FET), dewetting largely destroys the possibility for obtaining a compact and continuous crystalline thin organic semiconductor film and thus limits the mobility in these systems. Using oligothiophenes, we present an approach where the initial dewetting process can be turned into an advantage for generating very thin but large crystalline domains of a size up to the millimetres with all molecules sharing a single orientation. Our approach can be easily extended to other molecules, which have strongly differing growth velocities in the various directions of the crystal, for example due to directional pi-stacking interactions. FETs devices based on such large crystalline domains showed charge carrier mobilities that were two orders of magnitude higher compared to non-crystallized films. |
Gibot, Pierre; Vidal, Loic; Laffont, Lydia; Mory, Julien Zirconia nanopowder synthesis via detonation of trinitrotoluene Article de journal Ceramics International, 46 (17), p. 27057–27062, 2020. @article{Gibot2020, title = {Zirconia nanopowder synthesis via detonation of trinitrotoluene}, author = { Pierre Gibot and Loic Vidal and Lydia Laffont and Julien Mory}, doi = {10.1016/j.ceramint.2020.07.182}, year = {2020}, date = {2020-12-01}, journal = {Ceramics International}, volume = {46}, number = {17}, pages = {27057--27062}, abstract = {Zirconium (IV) oxide nanopowder was successfully synthesized through the detonation of a mixture composed of 2,4,6 trinitrotoluene (TNT, C7H5N3O6) and zirconium sulfate tetrahydrate (Zr(SO4)(2)center dot 4H(2)O) as the energetic material and ceramic precursor, respectively. TNT, one of the most popular explosives, is a secondary energetic molecule and exhibits high stability and low sensitivity toward external stresses, making its handling safe. After detonation of the energetic material/ceramic precursor mixture and purification of the detonation soot, a crystallized zirconium oxide (ZrO2) powder composed of nanosized particles with a spherical morphology was produced and analysed by the usual characterization techniques (X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and nitrogen physisorption). The reaction mechanism, considering the thermochemical aspect of the explosive, is offered. This approach could provide promising opportunities for the synthesis of various nano-sized oxide ceramic powders.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Zirconium (IV) oxide nanopowder was successfully synthesized through the detonation of a mixture composed of 2,4,6 trinitrotoluene (TNT, C7H5N3O6) and zirconium sulfate tetrahydrate (Zr(SO4)(2)center dot 4H(2)O) as the energetic material and ceramic precursor, respectively. TNT, one of the most popular explosives, is a secondary energetic molecule and exhibits high stability and low sensitivity toward external stresses, making its handling safe. After detonation of the energetic material/ceramic precursor mixture and purification of the detonation soot, a crystallized zirconium oxide (ZrO2) powder composed of nanosized particles with a spherical morphology was produced and analysed by the usual characterization techniques (X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and nitrogen physisorption). The reaction mechanism, considering the thermochemical aspect of the explosive, is offered. This approach could provide promising opportunities for the synthesis of various nano-sized oxide ceramic powders. |
Mau, Alexandre; Le, Thi Huong; Dietlin, Celine; Bui, Thanh-Tuan; Graff, Bernadette; Dumur, Frederic; Goubard, Fabrice; Lalevee, Jacques Donor-acceptor-donor structured thioxanthone derivatives as visible photoinitiators Article de journal Polymer Chemistry, 11 (45), p. 7221–7234, 2020. @article{Mau2020, title = {Donor-acceptor-donor structured thioxanthone derivatives as visible photoinitiators}, author = { Alexandre Mau and Thi Huong Le and Celine Dietlin and Thanh-Tuan Bui and Bernadette Graff and Frederic Dumur and Fabrice Goubard and Jacques Lalevee}, doi = {10.1039/d0py01244k}, year = {2020}, date = {2020-12-01}, journal = {Polymer Chemistry}, volume = {11}, number = {45}, pages = {7221--7234}, abstract = {Three thioxanthone derivatives differing by their peripheral groups have been investigated as visible light photoinitiators of polymerisation. Their reactivity and efficiency have been compared with that of a commercial type II photoinitiator (2-isopropylthioxanthone - ITX) in the case of free radical polymerisation, cationic polymerisation and interpenetrated polymer networks synthesis for 25 mu m or 1.4 mm thick samples under 405 nm LED irradiation. They are incorporated into either, a two-component system with an iodonium salt or an amine, or a three-component system combining an iodonium salt and an amine. Using absorption and fluorescence spectroscopies, laser flash photolysis and molecular modelling, optical properties, excited state energies and lifetimes of these thioxanthone derivatives have been determined allowing a better understanding of the associated chemical mechanisms. Interestingly, the main reaction pathway for one of these thioxanthone derivatives in the photoinitiating systems was determined as involving its singlet state S-1 whereas ITX and thioxanthones are known to react from their triplet excited state T-1. The high efficiency of the new initiating systems was found as being worthwhile for laser write applications @405 nm but also for high migration stability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Three thioxanthone derivatives differing by their peripheral groups have been investigated as visible light photoinitiators of polymerisation. Their reactivity and efficiency have been compared with that of a commercial type II photoinitiator (2-isopropylthioxanthone - ITX) in the case of free radical polymerisation, cationic polymerisation and interpenetrated polymer networks synthesis for 25 mu m or 1.4 mm thick samples under 405 nm LED irradiation. They are incorporated into either, a two-component system with an iodonium salt or an amine, or a three-component system combining an iodonium salt and an amine. Using absorption and fluorescence spectroscopies, laser flash photolysis and molecular modelling, optical properties, excited state energies and lifetimes of these thioxanthone derivatives have been determined allowing a better understanding of the associated chemical mechanisms. Interestingly, the main reaction pathway for one of these thioxanthone derivatives in the photoinitiating systems was determined as involving its singlet state S-1 whereas ITX and thioxanthones are known to react from their triplet excited state T-1. The high efficiency of the new initiating systems was found as being worthwhile for laser write applications @405 nm but also for high migration stability. |
Breakspear, Steven; Ivanov, Dimitri A; Noecker, Bernd; Popescu, Crisan Nanomechanical properties of Monilethrix affected hair are independent of phenotype. Article de journal Journal of structural biology, 213 (1), p. 107679–107679, 2020. @article{Breakspear2020, title = {Nanomechanical properties of Monilethrix affected hair are independent of phenotype.}, author = { Steven Breakspear and Dimitri A. Ivanov and Bernd Noecker and Crisan Popescu}, doi = {10.1016/j.jsb.2020.107679}, year = {2020}, date = {2020-12-01}, journal = {Journal of structural biology}, volume = {213}, number = {1}, pages = {107679--107679}, abstract = {Utilising the AFM nanoindentation technique for the study of hair cross- and longitudinal sections, the mechanical anisotropy of human hair fibres affected by a rare congenital condition, Monilethrix, has been investigated for the first time. Supported by X-ray microdiffraction data, and applying a model based on an ideal composite material consisting of rods (KIFs) and matrix (KAPs) to Monilethrix affected fibres, it has been shown that the results could be grouped into clearly different classes, namely: almost isotropic behaviour for Monilethrix affected hairs and anisotropic behaviour for Control hair. Moreover, AFM nanoindentation of hair cross sections has demonstrated, also for the first time that hairs affected by Monilethrix have a continuous, and not periodic, weakness within the cortex. This has been attributed to disruptions in the KIF-KIF, KIF-intermacrofibrillar matrix or KIF-desmosome complexes within the hair shaft, as suggested by X-ray microdiffraction examination. Hairs from a patient exhibiting no obvious phenotype exhibited similar mechanical weakness despite the otherwise normal visual appearance of the fibre. This further supports a hypothesis that the beaded appearance of Monilethrix hair is a secondary factor, unrelated to the inherent structural weakness.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Utilising the AFM nanoindentation technique for the study of hair cross- and longitudinal sections, the mechanical anisotropy of human hair fibres affected by a rare congenital condition, Monilethrix, has been investigated for the first time. Supported by X-ray microdiffraction data, and applying a model based on an ideal composite material consisting of rods (KIFs) and matrix (KAPs) to Monilethrix affected fibres, it has been shown that the results could be grouped into clearly different classes, namely: almost isotropic behaviour for Monilethrix affected hairs and anisotropic behaviour for Control hair. Moreover, AFM nanoindentation of hair cross sections has demonstrated, also for the first time that hairs affected by Monilethrix have a continuous, and not periodic, weakness within the cortex. This has been attributed to disruptions in the KIF-KIF, KIF-intermacrofibrillar matrix or KIF-desmosome complexes within the hair shaft, as suggested by X-ray microdiffraction examination. Hairs from a patient exhibiting no obvious phenotype exhibited similar mechanical weakness despite the otherwise normal visual appearance of the fibre. This further supports a hypothesis that the beaded appearance of Monilethrix hair is a secondary factor, unrelated to the inherent structural weakness. |
Dahou, Tilia; Defoort, Francoise; Jeguirim, Mejdi; Dupont, Capucine Towards understanding the role of K during biomass steam gasification Article de journal Fuel, 282 , p. 118806, 2020. @article{Dahou2020a, title = {Towards understanding the role of K during biomass steam gasification}, author = { Tilia Dahou and Francoise Defoort and Mejdi Jeguirim and Capucine Dupont}, doi = {10.1016/j.fuel.2020.118806}, year = {2020}, date = {2020-12-01}, journal = {Fuel}, volume = {282}, pages = {118806}, abstract = {Steam gasification is known to be catalyzed by K. However, the exact mechanisms are not identified to this day. In the present study, the catalytic influence of K on biomass steam gasification and its interaction with Si was investigated. The study was conducted through thermogravimetric analysis (TGA) on rice husks as a Si-rich biomass and K2CO3 as a model K-compound. Experiments were conducted in three different configurations: biomass or inorganic compound alone; mixtures of biomass and inorganic powders; biomass and inorganic compound without contact in a two-compartment crucible. It was shown that K has a catalytic effect on both the pyrolysis and the gasification steps. These effects occur even when the K-compound is not in direct contact with the biomass. Therefore, it demonstrates that the mechanisms involve the gas phase through the volatilization of a K-compound, most likely KOH(g). However, the observed catalytic effect on rice husks was weaker than the effect obtained in the case of beech wood, a Si-poor and more generally ash-poor biomass, under the same conditions. It shows that there is a competition between i) the influence of K on the biomass pyrolysis and char gasification kinetics and ii) the interaction of K with SiO2 inherent to the biomass.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Steam gasification is known to be catalyzed by K. However, the exact mechanisms are not identified to this day. In the present study, the catalytic influence of K on biomass steam gasification and its interaction with Si was investigated. The study was conducted through thermogravimetric analysis (TGA) on rice husks as a Si-rich biomass and K2CO3 as a model K-compound. Experiments were conducted in three different configurations: biomass or inorganic compound alone; mixtures of biomass and inorganic powders; biomass and inorganic compound without contact in a two-compartment crucible. It was shown that K has a catalytic effect on both the pyrolysis and the gasification steps. These effects occur even when the K-compound is not in direct contact with the biomass. Therefore, it demonstrates that the mechanisms involve the gas phase through the volatilization of a K-compound, most likely KOH(g). However, the observed catalytic effect on rice husks was weaker than the effect obtained in the case of beech wood, a Si-poor and more generally ash-poor biomass, under the same conditions. It shows that there is a competition between i) the influence of K on the biomass pyrolysis and char gasification kinetics and ii) the interaction of K with SiO2 inherent to the biomass. |
Sukhawipat, Nathapong; Saetung, Nitinart; Pasetto, Pamela; Pilard, Jean-Francois; Bistac, Sophie; Saetung, Anuwat A novel high adhesion cationic waterborne polyurethane for green coating applications Article de journal Progress in Organic Coatings, 148 , p. 105854, 2020. @article{Sukhawipat2020, title = {A novel high adhesion cationic waterborne polyurethane for green coating applications}, author = { Nathapong Sukhawipat and Nitinart Saetung and Pamela Pasetto and Jean-Francois Pilard and Sophie Bistac and Anuwat Saetung}, doi = {10.1016/j.porgcoat.2020.105854}, year = {2020}, date = {2020-11-01}, journal = {Progress in Organic Coatings}, volume = {148}, pages = {105854}, abstract = {This report is the first one on a cationic waterborne polyurethane (cWPU) latex based on epoxidized hydroxyl telechelic natural rubber (eHTNR) polyol, providing potential for use as a coating made of renewable resources. A cWPU latex was synthesized by step growth emulsion polymerization from hydroxyl telechelic natural rubber (HTNR with M-n = 3000 g.mol(-1)) with fixed N-methyl diethanol amine content of 5.6 wt% and 2,4-toluene diisocyanate (NCO index = 100). The effects of proportion of epoxide units on HTNR polyol from 0 to 30 % on preparing cWPU latex were investigated. Chemical structures of HTNR and eHTNR polyol were confirmed by H-1-NMR spectroscopy. The resulting HTNR and eHTNR polyols present a unimodal size exclusion chromatography trace. The viscosity increased with epoxide fraction. The synthesized cWPU latex based on eHTNR was a stable milky-blue emulsion with well-defined size dispersion. All cWPU-eHTNR films showed good wettability, good chemical resistance, and high thermal stability, improving with the proportion of epoxide units. The mechanical properties of cWPU-eHTNR films were studied from their stress-strain curves. Moreover, the electrical properties were investigated. The cWPU-eHTNR films showed relatively low conductivity. Wettability, chemical resistance, adhesion, thermal stability, and electrical properties of cWPU-HTNR films improved with the proportion of epoxide units on the HTNR polyol. These results demonstrate a new synthesis route to develop cWPU latex based on a biosource, for coating applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This report is the first one on a cationic waterborne polyurethane (cWPU) latex based on epoxidized hydroxyl telechelic natural rubber (eHTNR) polyol, providing potential for use as a coating made of renewable resources. A cWPU latex was synthesized by step growth emulsion polymerization from hydroxyl telechelic natural rubber (HTNR with M-n = 3000 g.mol(-1)) with fixed N-methyl diethanol amine content of 5.6 wt% and 2,4-toluene diisocyanate (NCO index = 100). The effects of proportion of epoxide units on HTNR polyol from 0 to 30 % on preparing cWPU latex were investigated. Chemical structures of HTNR and eHTNR polyol were confirmed by H-1-NMR spectroscopy. The resulting HTNR and eHTNR polyols present a unimodal size exclusion chromatography trace. The viscosity increased with epoxide fraction. The synthesized cWPU latex based on eHTNR was a stable milky-blue emulsion with well-defined size dispersion. All cWPU-eHTNR films showed good wettability, good chemical resistance, and high thermal stability, improving with the proportion of epoxide units. The mechanical properties of cWPU-eHTNR films were studied from their stress-strain curves. Moreover, the electrical properties were investigated. The cWPU-eHTNR films showed relatively low conductivity. Wettability, chemical resistance, adhesion, thermal stability, and electrical properties of cWPU-HTNR films improved with the proportion of epoxide units on the HTNR polyol. These results demonstrate a new synthesis route to develop cWPU latex based on a biosource, for coating applications. |
Pimentel, Carlos; Mougin, Karine; Gnecco, Enrico; Pina, Carlos M Journal of Crystal Growth, 550 , p. 125892, 2020. @article{Pimentel2020, title = {Formation of zabuyelite, Li2CO3 , on dolomite and kutnohorite 10.4 surfaces from supersaturated and undersaturated solutions: Growth behavior and anomalous friction at the nanoscale}, author = { Carlos Pimentel and Karine Mougin and Enrico Gnecco and Carlos M. Pina}, doi = {10.1016/j.jcrysgro.2020.125892}, year = {2020}, date = {2020-11-01}, journal = {Journal of Crystal Growth}, volume = {550}, pages = {125892}, abstract = {Cleaved dolomite (CaMg(CO3)(2)) crystals were immersed in supersaturated, saturated, and undersaturated solutions with respect to zabuyelite (Li2CO3), and the growth process was characterized using atomic force microscopy (AFM) and scanning electron microscopy (SEM). In all cases, overgrowths formed by 2D-nucleation could be clearly distinguished in the lateral force images recorded by AFM. With highly supersaturated solutions, AFM imaging was hindered by the formation of 3D crystal aggregates. When saturated solutions were used, the overgrowths reproduce the topography of the substrates, indicating that the lattice of the overgrown phase undergoes a compressive strain. Furthermore, we performed a nanotribological characterization by sliding a nanotip over both the 2D-overgrowths and dolomite substrates. Thus, friction coefficients, ti, could be easily quantified. As a result, a mu = 0.08 on the 2D-overgrowths was measured, which is one order of magnitude lower than the value of mu = 0.89 on the dolomite substrate. This friction reduction in the sliding of a nanotip on the overgrowth as compared to the friction observed on the dolomite substrate, together with the fact that atomicscale stick-slip is observed on dolomite but not on the 2D overgrowths, point towards an anomalously weak interaction of Li2CO3 overgrowths with the AFM probe.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cleaved dolomite (CaMg(CO3)(2)) crystals were immersed in supersaturated, saturated, and undersaturated solutions with respect to zabuyelite (Li2CO3), and the growth process was characterized using atomic force microscopy (AFM) and scanning electron microscopy (SEM). In all cases, overgrowths formed by 2D-nucleation could be clearly distinguished in the lateral force images recorded by AFM. With highly supersaturated solutions, AFM imaging was hindered by the formation of 3D crystal aggregates. When saturated solutions were used, the overgrowths reproduce the topography of the substrates, indicating that the lattice of the overgrown phase undergoes a compressive strain. Furthermore, we performed a nanotribological characterization by sliding a nanotip over both the 2D-overgrowths and dolomite substrates. Thus, friction coefficients, ti, could be easily quantified. As a result, a mu = 0.08 on the 2D-overgrowths was measured, which is one order of magnitude lower than the value of mu = 0.89 on the dolomite substrate. This friction reduction in the sliding of a nanotip on the overgrowth as compared to the friction observed on the dolomite substrate, together with the fact that atomicscale stick-slip is observed on dolomite but not on the 2D overgrowths, point towards an anomalously weak interaction of Li2CO3 overgrowths with the AFM probe. |
Largo, Fadwa; Haounati, Redouane; Akhouairi, Siham; Ouachtak, Hassan; Haouti, Rachid El; Guerdaoui, Anouar El; Hafid, Naima; Santos, Diogo M F; Akbal, Feryal; Kuleyin, Ayse; Jada, Amane; Addi, Abdelaziz Ait Adsorptive removal of both cationic and anionic dyes by using sepiolite clay mineral as adsorbent: Experimental and molecular dynamic simulation studies Article de journal Journal of Molecular Liquids, 318 , p. 114247, 2020. @article{Largo2020, title = {Adsorptive removal of both cationic and anionic dyes by using sepiolite clay mineral as adsorbent: Experimental and molecular dynamic simulation studies}, author = { Fadwa Largo and Redouane Haounati and Siham Akhouairi and Hassan Ouachtak and Rachid El Haouti and Anouar El Guerdaoui and Naima Hafid and Diogo M. F. Santos and Feryal Akbal and Ayse Kuleyin and Amane Jada and Abdelaziz Ait Addi}, doi = {10.1016/j.molliq.2020.114247}, year = {2020}, date = {2020-11-01}, journal = {Journal of Molecular Liquids}, volume = {318}, pages = {114247}, abstract = {In the present work, sepiolite clay was assessed as an adsorbent for the removal of cationic (Methylene Blue: MB) and anionic (Direct Red-23: DR-23) dyes from aqueous media. Firstly, the sepiolite clay mineral was characterized using different instrumental techniques viz., XRD, SEM, EDX, FIR, X-ray Fluorescence, and BET analysis. Thereafter, the adsorption study was examined as a function of the adsorbent amount, the contact time, the aqueous phase pH, the ionic strength, and the initial dye amount. The data indicate that the adsorption was a function of the pH with high adsorption amounts of MB and DR-23, in basic and acidic, respectively, pH ranges. By comparing experimental data to the Langmuir predictions, the calculated maximum dye adsorbed amounts were 124.9 and 649.37 mg g(-1), for MB and DR-23, respectively. Further, kinetic adsorption studies have shown that adsorption of MB and DR-23 from aqueous media onto the sepiolite follow, respectively, the pseudo-second order and the pseudo first-order kinetic models. On the other hand, Molecular Dynamic (MD) simulations were performed to shed light on the pH-effect on the adsorptive properties of the sepiolite clay surface and the adsorption behavior of both hazardous MB and DR-23 dyes into the adsorbent surface. The better affinity of the MB molecules toward the sepiolite in the basic media could be related to the dispersion forces and electrostatic interactions. On the other hand, the DR-23 molecules show more favorable interaction in the acidic media as a result of the hydrogen bonds formed between the dye molecule and the sepiolite surface oxygen atoms. In addition, the negative values of interaction energies calculated show that the adsorption processes of both hazardous MB and DR-23 molecules on the sepiolite surface are spontaneous, which is in good agreement with the results observed experimentally. (C) 2020 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the present work, sepiolite clay was assessed as an adsorbent for the removal of cationic (Methylene Blue: MB) and anionic (Direct Red-23: DR-23) dyes from aqueous media. Firstly, the sepiolite clay mineral was characterized using different instrumental techniques viz., XRD, SEM, EDX, FIR, X-ray Fluorescence, and BET analysis. Thereafter, the adsorption study was examined as a function of the adsorbent amount, the contact time, the aqueous phase pH, the ionic strength, and the initial dye amount. The data indicate that the adsorption was a function of the pH with high adsorption amounts of MB and DR-23, in basic and acidic, respectively, pH ranges. By comparing experimental data to the Langmuir predictions, the calculated maximum dye adsorbed amounts were 124.9 and 649.37 mg g(-1), for MB and DR-23, respectively. Further, kinetic adsorption studies have shown that adsorption of MB and DR-23 from aqueous media onto the sepiolite follow, respectively, the pseudo-second order and the pseudo first-order kinetic models. On the other hand, Molecular Dynamic (MD) simulations were performed to shed light on the pH-effect on the adsorptive properties of the sepiolite clay surface and the adsorption behavior of both hazardous MB and DR-23 dyes into the adsorbent surface. The better affinity of the MB molecules toward the sepiolite in the basic media could be related to the dispersion forces and electrostatic interactions. On the other hand, the DR-23 molecules show more favorable interaction in the acidic media as a result of the hydrogen bonds formed between the dye molecule and the sepiolite surface oxygen atoms. In addition, the negative values of interaction energies calculated show that the adsorption processes of both hazardous MB and DR-23 molecules on the sepiolite surface are spontaneous, which is in good agreement with the results observed experimentally. (C) 2020 Elsevier B.V. All rights reserved. |
Brunet, Sylvette; Lebeau, Benedicte; Naboulsi, Issam; Michelin, Laure; Comparot, Jean Dominique; Marichal, Claire; Rigolet, Severinne; Bonne, Magali; Blin, Jean-Luc Effect of Mesostructured Zirconia Support on the Activity and Selectivity of 4,6-Dimethydibenzothiophene Hydrodesulfurization Article de journal Catalysts, 10 (10), p. 1162, 2020. @article{Brunet2020, title = {Effect of Mesostructured Zirconia Support on the Activity and Selectivity of 4,6-Dimethydibenzothiophene Hydrodesulfurization}, author = { Sylvette Brunet and Benedicte Lebeau and Issam Naboulsi and Laure Michelin and Jean Dominique Comparot and Claire Marichal and Severinne Rigolet and Magali Bonne and Jean-Luc Blin}, doi = {10.3390/catal10101162}, year = {2020}, date = {2020-10-01}, journal = {Catalysts}, volume = {10}, number = {10}, pages = {1162}, abstract = {In contrast with the conventional CoMoS/alumina catalyst, the use of amorphous mesostructured ZrO2 as support for the dispersion of the CoMoS active phase in deep hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene led to a higher promotion rate and a better sulfidation of the cobalt species. The CoMoS, dispersed over mesostructured amorphous ZrO2 as catalyst, also induced a modification of the main desulfurization way; in this case, a shift towards direct desulfurization selectivity was observed. This result was unexpected regarding the literature. Indeed, the hydrogenated route was observed for commercial zirconia. The designed catalysts are therefore more eco-friendly, since they consume less hydrogen. This implies a better use of the fossil resources.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In contrast with the conventional CoMoS/alumina catalyst, the use of amorphous mesostructured ZrO2 as support for the dispersion of the CoMoS active phase in deep hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene led to a higher promotion rate and a better sulfidation of the cobalt species. The CoMoS, dispersed over mesostructured amorphous ZrO2 as catalyst, also induced a modification of the main desulfurization way; in this case, a shift towards direct desulfurization selectivity was observed. This result was unexpected regarding the literature. Indeed, the hydrogenated route was observed for commercial zirconia. The designed catalysts are therefore more eco-friendly, since they consume less hydrogen. This implies a better use of the fossil resources. |
Sun, Ke; Liu, Shaohui; Pigot, Corentin; Brunel, Damien; Graff, Bernadette; Nechab, Malek; Gigmes, Didier; Morlet-Savary, Fabrice; Zhang, Yijun; Xiao, Pu; Dumur, Frederic; Lalevee, Jacques Catalysts, 10 (10), p. 1196, 2020. @article{Sun2020a, title = {Novel Push-Pull Dyes Derived from 1H-cyclopenta[b]naphthalene-1,3(2H)-dione as Versatile Photoinitiators for Photopolymerization and Their Related Applications: 3D Printing and Fabrication of Photocomposites}, author = { Ke Sun and Shaohui Liu and Corentin Pigot and Damien Brunel and Bernadette Graff and Malek Nechab and Didier Gigmes and Fabrice Morlet-Savary and Yijun Zhang and Pu Xiao and Frederic Dumur and Jacques Lalevee}, doi = {10.3390/catal10101196}, year = {2020}, date = {2020-10-01}, journal = {Catalysts}, volume = {10}, number = {10}, pages = {1196}, abstract = {A series of eleven push-pull chromophores with specific structures have been designed for the free radical polymerization of acrylates, but also for the fabrication of photocomposites and 3D-printed structures. New photoinitiating systems comprising the different push-pull dyes showed excellent photochemical reactivities at 405 nm. Notably, polymerization reactions could be initiated with light-emitting diodes (LEDs) which constitute a unique opportunity to promote the free radical polymerization under mild conditions, i.e., low light intensity (e.g., sunlight) and under air. Photopolymerization is an active research field, and push-pull dyes have already been investigated for this purpose. Besides, it remains of crucial interest to investigate new reactive structures capable of efficiently initiating photopolymerization reactions. The plausible potential of these structures to act as efficient photoinitiators in vat photopolymerization (or 3D printing) and fabrication of photocomposites prompts us to select eleven new push-pull dyes to design multi-component photoinitiating systems activable with LEDs emitting at 405 nm. Precisely, a tertiary amine, i.e., ethyl dimethylaminobenzoate (EDB) used as an electron/hydrogen donor and an iodonium salt used as an electron acceptor were selected to behave as powerful co-initiators to construct three-component photoinitiating systems (PISs) with the different push-pull dyes. Among these new PISs, dye 8 and 9-based PISs could efficiently promote the free radical photopolymerization of acrylates upon exposure to a LED emitting at 405 nm also upon sunlight irradiation, highlighting their huge performance. Photoinitiating abilities could be explained on the basis of steady state photolysis experiments. Fluorescence measurements and electron spin resonance (ESR) spin-trapping experiments were also performed to obtain a deeper insight into the chemical mechanisms supporting the polymerization reaction and determine the way the initiating species, i.e., the radicals, are observed. Finally, two investigated dye-based PISs were applied to the fabrications of photocomposites. Three-dimensional patterns with excellent spatial resolutions were generated by the laser writing technique to identify the effects of photopolymerization of acrylates both in the absence and presence of fillers (silica). Interestingly, comparison between the 3D objects fabricated by the PISs/monomer systems and the PISs/monomer/filler photocomposites indicates that the newly designed photocomposites are suitable for practical applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A series of eleven push-pull chromophores with specific structures have been designed for the free radical polymerization of acrylates, but also for the fabrication of photocomposites and 3D-printed structures. New photoinitiating systems comprising the different push-pull dyes showed excellent photochemical reactivities at 405 nm. Notably, polymerization reactions could be initiated with light-emitting diodes (LEDs) which constitute a unique opportunity to promote the free radical polymerization under mild conditions, i.e., low light intensity (e.g., sunlight) and under air. Photopolymerization is an active research field, and push-pull dyes have already been investigated for this purpose. Besides, it remains of crucial interest to investigate new reactive structures capable of efficiently initiating photopolymerization reactions. The plausible potential of these structures to act as efficient photoinitiators in vat photopolymerization (or 3D printing) and fabrication of photocomposites prompts us to select eleven new push-pull dyes to design multi-component photoinitiating systems activable with LEDs emitting at 405 nm. Precisely, a tertiary amine, i.e., ethyl dimethylaminobenzoate (EDB) used as an electron/hydrogen donor and an iodonium salt used as an electron acceptor were selected to behave as powerful co-initiators to construct three-component photoinitiating systems (PISs) with the different push-pull dyes. Among these new PISs, dye 8 and 9-based PISs could efficiently promote the free radical photopolymerization of acrylates upon exposure to a LED emitting at 405 nm also upon sunlight irradiation, highlighting their huge performance. Photoinitiating abilities could be explained on the basis of steady state photolysis experiments. Fluorescence measurements and electron spin resonance (ESR) spin-trapping experiments were also performed to obtain a deeper insight into the chemical mechanisms supporting the polymerization reaction and determine the way the initiating species, i.e., the radicals, are observed. Finally, two investigated dye-based PISs were applied to the fabrications of photocomposites. Three-dimensional patterns with excellent spatial resolutions were generated by the laser writing technique to identify the effects of photopolymerization of acrylates both in the absence and presence of fillers (silica). Interestingly, comparison between the 3D objects fabricated by the PISs/monomer systems and the PISs/monomer/filler photocomposites indicates that the newly designed photocomposites are suitable for practical applications. |
Rahal, Mahmoud; Mokbel, Haifaa; Graff, Bernadette; Toufaily, Joumana; Hamieh, Tayssir; Dumur, Frederic; Lalevee, Jacques Mono vs. Difunctional Coumarin as Photoinitiators in Photocomposite Synthesis and 3D Printing Article de journal Catalysts, 10 (10), p. 1202, 2020. @article{Rahal2020a, title = {Mono vs. Difunctional Coumarin as Photoinitiators in Photocomposite Synthesis and 3D Printing}, author = { Mahmoud Rahal and Haifaa Mokbel and Bernadette Graff and Joumana Toufaily and Tayssir Hamieh and Frederic Dumur and Jacques Lalevee}, doi = {10.3390/catal10101202}, year = {2020}, date = {2020-10-01}, journal = {Catalysts}, volume = {10}, number = {10}, pages = {1202}, abstract = {This work is devoted to investigate three coumarin derivatives (Coum1, Coum2, and Coum3), proposed as new photoinitiators of polymerization when combined with an additive, i.e., an iodonium salt, and used for the free radical polymerization (FRP) of acrylate monomers under mild irradiation conditions. The different coumarin derivatives can also be employed in three component photoinitiating systems with a Iod/amine (ethyl 4-dimethylaminobenzoate (EDB) or N-phenylglycine (NPG)) couple for FRP upon irradiation with an LED @ 405 nm. These compounds showed excellent photoinitiating abilities, and high polymerization rates and final conversions (FC) were obtained. The originality of this work relies on the comparison of the photoinitiating abilities of monofunctional (Coum1 and Coum2) vs. difunctional (Coum3) compounds. Coum3 is a combined structure of Coum1 and Coum2, leading to a sterically hindered chemical structure with a relatively high molecular weight. As a general rule, a high molecular weight should reduce the migration of initiating molecules and favor photochemical properties such as photobleaching of the final polymer. As attempted, from the efficiency point of view, Coum3 can initiate the FRP, but a low reactivity was observed compared to the monofunctional compound (Coum1 and Coum2). Indeed, to study the photochemical and photophysical properties of these compounds, different parameters were taken into account, e.g., the light absorption and emission properties, steady state photolysis, and fluorescence quenching. To examine these different points, several techniques were used including UV-visible spectroscopy, real-time Fourier Transform Infrared Spectroscopy (RT-FTIR), fluorescence spectroscopy, and cyclic voltammetry. The photochemical mechanism involved in the polymerization process is also detailed. The best coumarins investigated in this work were used for laser writing (3D printing) experiments and also for photocomposite synthesis containing glass fibers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work is devoted to investigate three coumarin derivatives (Coum1, Coum2, and Coum3), proposed as new photoinitiators of polymerization when combined with an additive, i.e., an iodonium salt, and used for the free radical polymerization (FRP) of acrylate monomers under mild irradiation conditions. The different coumarin derivatives can also be employed in three component photoinitiating systems with a Iod/amine (ethyl 4-dimethylaminobenzoate (EDB) or N-phenylglycine (NPG)) couple for FRP upon irradiation with an LED @ 405 nm. These compounds showed excellent photoinitiating abilities, and high polymerization rates and final conversions (FC) were obtained. The originality of this work relies on the comparison of the photoinitiating abilities of monofunctional (Coum1 and Coum2) vs. difunctional (Coum3) compounds. Coum3 is a combined structure of Coum1 and Coum2, leading to a sterically hindered chemical structure with a relatively high molecular weight. As a general rule, a high molecular weight should reduce the migration of initiating molecules and favor photochemical properties such as photobleaching of the final polymer. As attempted, from the efficiency point of view, Coum3 can initiate the FRP, but a low reactivity was observed compared to the monofunctional compound (Coum1 and Coum2). Indeed, to study the photochemical and photophysical properties of these compounds, different parameters were taken into account, e.g., the light absorption and emission properties, steady state photolysis, and fluorescence quenching. To examine these different points, several techniques were used including UV-visible spectroscopy, real-time Fourier Transform Infrared Spectroscopy (RT-FTIR), fluorescence spectroscopy, and cyclic voltammetry. The photochemical mechanism involved in the polymerization process is also detailed. The best coumarins investigated in this work were used for laser writing (3D printing) experiments and also for photocomposite synthesis containing glass fibers. |
Frikha, Kawthar; Limousy, Lionel; Bouaziz, Jamel; Chaari, Kamel; Bennici, Simona Synthesis, Characterization and Catalytic Activity of Ternary Oxide Catalysts Using the Microwave-Assisted Solution Combustion Method Article de journal Materials, 13 (20), p. 4607, 2020. @article{Frikha2020a, title = {Synthesis, Characterization and Catalytic Activity of Ternary Oxide Catalysts Using the Microwave-Assisted Solution Combustion Method}, author = { Kawthar Frikha and Lionel Limousy and Jamel Bouaziz and Kamel Chaari and Simona Bennici}, doi = {10.3390/ma13204607}, year = {2020}, date = {2020-10-01}, journal = {Materials}, volume = {13}, number = {20}, pages = {4607}, abstract = {Ni-Co-Al, Ni-Cu-Al and Co-Cu-Al ternary oxide catalysts, with a fixed 5 wt% transition metal loading, were prepared by the microwave-assisted solution combustion method and tested in CO oxidation. The bulk and surface properties of the catalysts were investigated, using XRD, N-2 adsorption-desorption, SEM, XPS and TEM techniques. XRD, XPS and TEM results revealed that nickel and cobalt were present as spinels on the surface and in the bulk. Differently, copper was preferentially present in "bulk-like" CuO-segregated phases. No interaction between the couples of transition metal species was detected, and the introduction of Cu-containing precursors into the Ni-Al or Co-Al combustion systems was not effective in preventing the formation of NiAl2O4 and CoAl2O4 spinels in the Ni- or Co-containing catalysts. Copper-containing catalysts were the most active, indicating that copper oxides are the effective active species for improving the CO oxidation activity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ni-Co-Al, Ni-Cu-Al and Co-Cu-Al ternary oxide catalysts, with a fixed 5 wt% transition metal loading, were prepared by the microwave-assisted solution combustion method and tested in CO oxidation. The bulk and surface properties of the catalysts were investigated, using XRD, N-2 adsorption-desorption, SEM, XPS and TEM techniques. XRD, XPS and TEM results revealed that nickel and cobalt were present as spinels on the surface and in the bulk. Differently, copper was preferentially present in "bulk-like" CuO-segregated phases. No interaction between the couples of transition metal species was detected, and the introduction of Cu-containing precursors into the Ni-Al or Co-Al combustion systems was not effective in preventing the formation of NiAl2O4 and CoAl2O4 spinels in the Ni- or Co-containing catalysts. Copper-containing catalysts were the most active, indicating that copper oxides are the effective active species for improving the CO oxidation activity. |
Enneiymy, Mohamed; Fioux, Philippe; Drian, Claude Le; Ghimbeu, Camelia Matei; Becht, Jean-Michel Palladium nanoparticles embedded in mesoporous carbons as efficient, green and reusable catalysts for mild hydrogenations of nitroarenes Article de journal Rsc Advances, 10 (60), p. 36741–36750, 2020. @article{Enneiymy2020, title = {Palladium nanoparticles embedded in mesoporous carbons as efficient, green and reusable catalysts for mild hydrogenations of nitroarenes}, author = { Mohamed Enneiymy and Philippe Fioux and Claude Le Drian and Camelia Matei Ghimbeu and Jean-Michel Becht}, doi = {10.1039/d0ra05713d}, year = {2020}, date = {2020-10-01}, journal = {Rsc Advances}, volume = {10}, number = {60}, pages = {36741--36750}, abstract = {The reduction of nitroarenes is the most efficient route for the preparation of aromatic primary amines. These reductions are generally performed in the presence of heterogeneous transition metal catalysts, which are rather efficient but long and tedious to prepare. In addition, they contain very expensive metals that are in most cases difficult to reuse. Therefore, the development of efficient, easily accessible and reusable Pd catalysts obtained rapidly from safe and non-toxic starting materials was implemented in this report. Two bottom-up synthesis methods were used, the first consisted in the impregnation of a micro/mesoporous carbon support with a Pd salt solution, followed by thermal reduction (at 300, 450 or 600 degrees C) while the second involved a direct synthesis based on the co-assembly and pyrolysis (600 degrees C) of a mixture of a phenolic precursor, glyoxal, a surfactant and a Pd salt. The obtained composites possess Pd nanoparticles (NPs) of tunable sizes (ranging from 1-2 to 7.0 nm) and homogeneously distributed in the carbon framework (pores/walls). It turned out that they were successfully used for mild and environment-friendly hydrogenations of nitroarenes at room temperature under H-2(1 atm) in EtOH in the presence of only 5 mequiv. of supported Pd. The determinations of the optimal characteristics of the catalysts constituted a second objective of this study. It was found that the activity of the catalysts was strongly dependent on the Pd NPs sizes,i.e., catalysts bearing small Pd NPs (1.2 nm obtained at 300 degrees C and 3.4 nm obtained at 450 degrees C) exhibited an excellent activity, while those containing larger Pd NPs (6.4 nm and 7.0 nm obtained at 600 degrees C, either by indirect or direct methods) were not active. Moreover, the possibility to reuse the catalysts was shown to be dependent on the surface chemistry of the Pd NPs: the smallest Pd NPs are prone to oxidation by air and their surface was gradually covered by a PdO shell decreasing their activity during reuse. A good compromise between intrinsic catalytic activity (i.e. during first use) and possibility of reuse was found in the catalyst made by impregnation followed by reduction at 450 degrees C since the hydrogenation could be performed in only 2 h in EtOH or even in water. The catalyst was quantitatively recovered after reaction by filtration, used at least 7 times with no loss of efficiency. Advantageously, almost Pd-free primary aromatic amines were obtained since the Pd leaching was very low (<0.1% of the introduced amount). Compared to numerous reports from the literature, the catalysts described here were both easily accessible from eco-friendly precursors and very active for hydrogenations under mild and "green" reaction conditions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The reduction of nitroarenes is the most efficient route for the preparation of aromatic primary amines. These reductions are generally performed in the presence of heterogeneous transition metal catalysts, which are rather efficient but long and tedious to prepare. In addition, they contain very expensive metals that are in most cases difficult to reuse. Therefore, the development of efficient, easily accessible and reusable Pd catalysts obtained rapidly from safe and non-toxic starting materials was implemented in this report. Two bottom-up synthesis methods were used, the first consisted in the impregnation of a micro/mesoporous carbon support with a Pd salt solution, followed by thermal reduction (at 300, 450 or 600 degrees C) while the second involved a direct synthesis based on the co-assembly and pyrolysis (600 degrees C) of a mixture of a phenolic precursor, glyoxal, a surfactant and a Pd salt. The obtained composites possess Pd nanoparticles (NPs) of tunable sizes (ranging from 1-2 to 7.0 nm) and homogeneously distributed in the carbon framework (pores/walls). It turned out that they were successfully used for mild and environment-friendly hydrogenations of nitroarenes at room temperature under H-2(1 atm) in EtOH in the presence of only 5 mequiv. of supported Pd. The determinations of the optimal characteristics of the catalysts constituted a second objective of this study. It was found that the activity of the catalysts was strongly dependent on the Pd NPs sizes,i.e., catalysts bearing small Pd NPs (1.2 nm obtained at 300 degrees C and 3.4 nm obtained at 450 degrees C) exhibited an excellent activity, while those containing larger Pd NPs (6.4 nm and 7.0 nm obtained at 600 degrees C, either by indirect or direct methods) were not active. Moreover, the possibility to reuse the catalysts was shown to be dependent on the surface chemistry of the Pd NPs: the smallest Pd NPs are prone to oxidation by air and their surface was gradually covered by a PdO shell decreasing their activity during reuse. A good compromise between intrinsic catalytic activity (i.e. during first use) and possibility of reuse was found in the catalyst made by impregnation followed by reduction at 450 degrees C since the hydrogenation could be performed in only 2 h in EtOH or even in water. The catalyst was quantitatively recovered after reaction by filtration, used at least 7 times with no loss of efficiency. Advantageously, almost Pd-free primary aromatic amines were obtained since the Pd leaching was very low (<0.1% of the introduced amount). Compared to numerous reports from the literature, the catalysts described here were both easily accessible from eco-friendly precursors and very active for hydrogenations under mild and "green" reaction conditions. |
Noirbent, Guillaume; Xu, Yangyang; Bonardi, Aude-Heloise; Gigmes, Didier; Lalevee, Jacques; Dumur, Frederic Metalated porphyrins as versatile visible light and NIR photoinitiators of polymerization Article de journal European Polymer Journal, 139 , p. 110019, 2020. @article{Noirbent2020a, title = {Metalated porphyrins as versatile visible light and NIR photoinitiators of polymerization}, author = { Guillaume Noirbent and Yangyang Xu and Aude-Heloise Bonardi and Didier Gigmes and Jacques Lalevee and Frederic Dumur}, doi = {10.1016/j.eurpolymj.2020.110019}, year = {2020}, date = {2020-10-01}, journal = {European Polymer Journal}, volume = {139}, pages = {110019}, abstract = {A series of metalated porphyrins has been prepared and used as visible light photoinitiators of polymerization activable under low light intensity. Among the six metalated porphyrins examined in this work, five of them have never been reported in the literature and specifically designed to exhibit a good solubility in monomers. Three of the proposed structures were efficient @405 nm but remarkably, despites their weak absorptions at 785 nm, efficient Near Infrared (NIR) polymerization profiles could also be obtained during the free radical polymerization of a methacrylate resin. To support the experimental observation of a polymerization process, a mechanism has been proposed based on combined photochemical and photothermal pathways.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A series of metalated porphyrins has been prepared and used as visible light photoinitiators of polymerization activable under low light intensity. Among the six metalated porphyrins examined in this work, five of them have never been reported in the literature and specifically designed to exhibit a good solubility in monomers. Three of the proposed structures were efficient @405 nm but remarkably, despites their weak absorptions at 785 nm, efficient Near Infrared (NIR) polymerization profiles could also be obtained during the free radical polymerization of a methacrylate resin. To support the experimental observation of a polymerization process, a mechanism has been proposed based on combined photochemical and photothermal pathways. |
Wittmann, Bernd; Wiesneth, Stephan; Motamen, Sajedeh; Simon, Laurent; Serein-Spirau, Francoise; Reiter, Guenter; Hildner, Richard Energy transport and light propagation mechanisms in organic single crystals Article de journal Journal of Chemical Physics, 153 (14), p. 144202, 2020. @article{Wittmann2020, title = {Energy transport and light propagation mechanisms in organic single crystals}, author = { Bernd Wittmann and Stephan Wiesneth and Sajedeh Motamen and Laurent Simon and Francoise Serein-Spirau and Guenter Reiter and Richard Hildner}, doi = {10.1063/5.0019832}, year = {2020}, date = {2020-10-01}, journal = {Journal of Chemical Physics}, volume = {153}, number = {14}, pages = {144202}, abstract = {Unambiguous information about spatiotemporal exciton dynamics in three-dimensional nanometer- to micrometer-sized organic structures is difficult to obtain experimentally. Exciton dynamics can be modified by annihilation processes, and different light propagation mechanisms can take place, such as active waveguiding and photon recycling. Since these various processes and mechanisms can lead to similar spectroscopic and microscopic signatures on comparable time scales, their discrimination is highly demanding. Here, we study individual organic single crystals grown from thiophene-based oligomers. We use time-resolved detection-beam scanning microscopy to excite a local singlet exciton population and monitor the subsequent broadening of the photoluminescence (PL) signal in space and on pico- to nanosecond time scales. Combined with Monte Carlo simulations, we were able to exclude photon recycling for our system, whereas leakage radiation upon active waveguiding leads to an apparent PL broadening of about 20% compared to the initial excitation profile. Exciton-exciton annihilation becomes important at high excitation fluence and apparently accelerates the exciton dynamics leading to apparently increased diffusion lengths. At low excitation fluences, the spatiotemporal PL broadening results from singlet exciton diffusion with diffusion lengths of up to 210 nm. Surprisingly, even in structurally highly ordered single crystals, the transport dynamics is subdiffusive and shows variations between different crystals, which we relate to varying degrees of static and dynamic electronic disorders.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Unambiguous information about spatiotemporal exciton dynamics in three-dimensional nanometer- to micrometer-sized organic structures is difficult to obtain experimentally. Exciton dynamics can be modified by annihilation processes, and different light propagation mechanisms can take place, such as active waveguiding and photon recycling. Since these various processes and mechanisms can lead to similar spectroscopic and microscopic signatures on comparable time scales, their discrimination is highly demanding. Here, we study individual organic single crystals grown from thiophene-based oligomers. We use time-resolved detection-beam scanning microscopy to excite a local singlet exciton population and monitor the subsequent broadening of the photoluminescence (PL) signal in space and on pico- to nanosecond time scales. Combined with Monte Carlo simulations, we were able to exclude photon recycling for our system, whereas leakage radiation upon active waveguiding leads to an apparent PL broadening of about 20% compared to the initial excitation profile. Exciton-exciton annihilation becomes important at high excitation fluence and apparently accelerates the exciton dynamics leading to apparently increased diffusion lengths. At low excitation fluences, the spatiotemporal PL broadening results from singlet exciton diffusion with diffusion lengths of up to 210 nm. Surprisingly, even in structurally highly ordered single crystals, the transport dynamics is subdiffusive and shows variations between different crystals, which we relate to varying degrees of static and dynamic electronic disorders. |
de Matos, Caroline Silva; Ghimbeu, Camelia Matei; Brendle, Jocelyne; Limousy, Lionel; Constantino, Vera Regina Leopoldo Thermal decomposition of a layered double hydroxide as a bottom up approach for the synthesis of metallic nanoparticles embedded in carbon structures Article de journal New Journal of Chemistry, 44 (39), p. 16721–16732, 2020. @article{Matos2020, title = {Thermal decomposition of a layered double hydroxide as a bottom up approach for the synthesis of metallic nanoparticles embedded in carbon structures}, author = { Caroline Silva de Matos and Camelia Matei Ghimbeu and Jocelyne Brendle and Lionel Limousy and Vera Regina Leopoldo Constantino}, doi = {10.1039/d0nj01938k}, year = {2020}, date = {2020-10-01}, journal = {New Journal of Chemistry}, volume = {44}, number = {39}, pages = {16721--16732}, abstract = {In the present study, the thermal behaviour of a layered double hydroxide (LDH) intercalated with a carboxymethylcellulose (CMC) polymer was evaluated to inspect the effect of the temperature on the chemical processes that occur during its decomposition under a nitrogen atmosphere, ranging from 500 to 1000 degrees C, as well as the product properties. The intercalation compound (LDH-CMC) proved to be a suitable precursor to develop inorganic nanocomposites based on Ni metallic nanoparticles (Ni-MNPs) embedded in a carbonaceous matrix by a bottom-up strategy involving a carbothermal reaction. Considering the temperature effect on the LDH-CMC decomposition processes, as well as the dispersion of metallic and carbon sources at the nanoscale level favoured by the intercalated structure, the simple synthetic approach reported in this work permits fine tuning of the production of valuable phases. The nanocomposites with ordered carbonaceous structures and transition metallic nanoparticles are interesting functional materials for electrocatalysis.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the present study, the thermal behaviour of a layered double hydroxide (LDH) intercalated with a carboxymethylcellulose (CMC) polymer was evaluated to inspect the effect of the temperature on the chemical processes that occur during its decomposition under a nitrogen atmosphere, ranging from 500 to 1000 degrees C, as well as the product properties. The intercalation compound (LDH-CMC) proved to be a suitable precursor to develop inorganic nanocomposites based on Ni metallic nanoparticles (Ni-MNPs) embedded in a carbonaceous matrix by a bottom-up strategy involving a carbothermal reaction. Considering the temperature effect on the LDH-CMC decomposition processes, as well as the dispersion of metallic and carbon sources at the nanoscale level favoured by the intercalated structure, the simple synthetic approach reported in this work permits fine tuning of the production of valuable phases. The nanocomposites with ordered carbonaceous structures and transition metallic nanoparticles are interesting functional materials for electrocatalysis. |
Tar, Haja; Kashar, Tahani I; Kouki, Noura; Aldawas, Reema; Graff, Bernadette; Lalevee, Jacques Novel Copper Photoredox Catalysts for Polymerization: An In Situ Synthesis of Metal Nanoparticles. Article de journal Polymers, 12 (10), 2020. @article{Tar2020, title = {Novel Copper Photoredox Catalysts for Polymerization: An In Situ Synthesis of Metal Nanoparticles.}, author = { Haja Tar and Tahani I. Kashar and Noura Kouki and Reema Aldawas and Bernadette Graff and Jacques Lalevee}, doi = {10.3390/polym12102293}, year = {2020}, date = {2020-10-01}, journal = {Polymers}, volume = {12}, number = {10}, abstract = {The copper II complex (HLCuCl) carrying 2,4 dinitrophenylhydrazone (L) is synthesized and evaluated as a new photoredox catalyst/photoinitiator in combination with triethylamine (TEA) and iodonium salt (Iod) for the radical polymerization of ethylene glycol diacrylate during exposure to visible light using a photoreactor at 419 nm. The copper complex reactivity with TEA/Iod salt/gold chloride showed a good production and stability of gold nanoparticles. Finally, the high performance of Cu (II) complex for radical photopolymerization incorporating gold nanoparticles is provided. The photochemical mechanisms for the production of initiating radicals are studied using cyclic voltammetry. Polymer nanocomposites containing gold nanoparticles (Au NPs) in situ photogenerated during the irradiation process were prepared. The formation of Au NPs inside the polymer matrix was through UV-Vis and EDS/SEM analyses.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The copper II complex (HLCuCl) carrying 2,4 dinitrophenylhydrazone (L) is synthesized and evaluated as a new photoredox catalyst/photoinitiator in combination with triethylamine (TEA) and iodonium salt (Iod) for the radical polymerization of ethylene glycol diacrylate during exposure to visible light using a photoreactor at 419 nm. The copper complex reactivity with TEA/Iod salt/gold chloride showed a good production and stability of gold nanoparticles. Finally, the high performance of Cu (II) complex for radical photopolymerization incorporating gold nanoparticles is provided. The photochemical mechanisms for the production of initiating radicals are studied using cyclic voltammetry. Polymer nanocomposites containing gold nanoparticles (Au NPs) in situ photogenerated during the irradiation process were prepared. The formation of Au NPs inside the polymer matrix was through UV-Vis and EDS/SEM analyses. |
2021 |
Riikonen, Joakim; Rantanen, Jimi; Thapa, Rinez; Le, Nguyen T; Rigolet, Severinne; Fioux, Philippe; Turhanen, Petri; Bodiford, Nelli K; Kalluri, Jhansi R; Ikonen, Timo; Nissinen, Tuomo; Lebeau, Benedicte; Vepsalainen, Jouko; Coffer, Jeffery L; Lehto, Vesa-Pekka Rapid synthesis of nanostructured porous silicon carbide from biogenic silica (Article de journal) Journal of the American Ceramic Society, 104 (2), p. 766–775, 2021. @article{Riikonen2021, title = {Rapid synthesis of nanostructured porous silicon carbide from biogenic silica}, author = { Joakim Riikonen and Jimi Rantanen and Rinez Thapa and Nguyen T. Le and Severinne Rigolet and Philippe Fioux and Petri Turhanen and Nelli K. Bodiford and Jhansi R. Kalluri and Timo Ikonen and Tuomo Nissinen and Benedicte Lebeau and Jouko Vepsalainen and Jeffery L. Coffer and Vesa-Pekka Lehto}, doi = {10.1111/jace.17519}, year = {2021}, date = {2021-02-01}, journal = {Journal of the American Ceramic Society}, volume = {104}, number = {2}, pages = {766--775}, abstract = {Nanostructured silicon carbide (SiC) is an exceptional material with numerous applications, for example, in catalysis, biomedicine, high-performance composites, and sensing. In this study, a fast and scalable method of producing nanostructured SiC from plant materials by magnesiothermic reduction via self-propagating high-temperature synthesis (SHS) route was developed. The produced biogenic material possessed a high surface area above 200 m(2)/g with a SiC crystallite size below 10 nm, which has not been done previously by SHS. This method enables affordable synthesis of the material plant-based precursors in a reaction that only takes a few seconds, thereby paving a way for nanostructured SiC production in high volumes using renewable resources. The material was also functionalized with carboxylic acid and bisphosphonate moieties, and its use as metal adsorbent in applications such as wastewater remediation was demonstrated.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Nanostructured silicon carbide (SiC) is an exceptional material with numerous applications, for example, in catalysis, biomedicine, high-performance composites, and sensing. In this study, a fast and scalable method of producing nanostructured SiC from plant materials by magnesiothermic reduction via self-propagating high-temperature synthesis (SHS) route was developed. The produced biogenic material possessed a high surface area above 200 m(2)/g with a SiC crystallite size below 10 nm, which has not been done previously by SHS. This method enables affordable synthesis of the material plant-based precursors in a reaction that only takes a few seconds, thereby paving a way for nanostructured SiC production in high volumes using renewable resources. The material was also functionalized with carboxylic acid and bisphosphonate moieties, and its use as metal adsorbent in applications such as wastewater remediation was demonstrated. |
Schobing, Julie; Cesario, Moises; Dorge, Sophie; Nouali, Habiba; Patarin, Joel; Martens, Johan; Brilhac, Jean-Francois CuO supported on COK-12 and SBA-15 ordered mesoporous materials for temperature swing SOx adsorption (Article de journal) Fuel Processing Technology, 211 , p. 106586, 2021. @article{Schobing2021, title = {CuO supported on COK-12 and SBA-15 ordered mesoporous materials for temperature swing SOx adsorption}, author = { Julie Schobing and Moises Cesario and Sophie Dorge and Habiba Nouali and Joel Patarin and Johan Martens and Jean-Francois Brilhac}, doi = {10.1016/j.fuproc.2020.106586}, year = {2021}, date = {2021-01-01}, journal = {Fuel Processing Technology}, volume = {211}, pages = {106586}, abstract = {Ordered mesoporous SBA-15 and COK-12 supports with similar mesopore diameter were loaded with 15 wt% of CuO and evaluated as adsorbents in a desulfurization process involving SOx adsorption and regeneration. Both SBA-15 and COK-12 have a hexagonal arrangement of parallel tubular mesopores. The impact of relatively small differences of the structural and textural properties of the two supports on SOx adsorption and regenerability is investigated. After impregnation with copper nitrate solution and calcination at 500 degrees C, the samples do not show any characteristic XRD pattern of copper-based phases, confirming the highly dispersed state of CuO, which is also checked by Transmission Electron Microscopy (TEM). The COK-CuO15 sample has slightly higher porosity than the SBA-CuO15 sample. The pore volume of both supports is slightly reduced after impregnation-calcination and shaping (Pelletized, Crushed and Sieved - PCS) steps. As for its SOx adsorptive properties, after fifteen adsorption-regeneration cycles at 400 degrees C, the COK-CuO15_PCS sample exhibits dynamic and total adsorption capacities higher than those of the SBA-CuO15_PCS adsorbent. In addition, both adsorbents preserve their adsorption capacities over the 15 cycles. The COK-12 support for the CuO active phase provides very promising results in comparison with the literature data for SBA-CuO15 adsorbent.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ordered mesoporous SBA-15 and COK-12 supports with similar mesopore diameter were loaded with 15 wt% of CuO and evaluated as adsorbents in a desulfurization process involving SOx adsorption and regeneration. Both SBA-15 and COK-12 have a hexagonal arrangement of parallel tubular mesopores. The impact of relatively small differences of the structural and textural properties of the two supports on SOx adsorption and regenerability is investigated. After impregnation with copper nitrate solution and calcination at 500 degrees C, the samples do not show any characteristic XRD pattern of copper-based phases, confirming the highly dispersed state of CuO, which is also checked by Transmission Electron Microscopy (TEM). The COK-CuO15 sample has slightly higher porosity than the SBA-CuO15 sample. The pore volume of both supports is slightly reduced after impregnation-calcination and shaping (Pelletized, Crushed and Sieved - PCS) steps. As for its SOx adsorptive properties, after fifteen adsorption-regeneration cycles at 400 degrees C, the COK-CuO15_PCS sample exhibits dynamic and total adsorption capacities higher than those of the SBA-CuO15_PCS adsorbent. In addition, both adsorbents preserve their adsorption capacities over the 15 cycles. The COK-12 support for the CuO active phase provides very promising results in comparison with the literature data for SBA-CuO15 adsorbent. |
Gencoglu, Turkan; Eren, Tugce Nur; Lalevee, Jacques; Avci, Duygu Photoinitiating systems based on poly(ethylene imine) for Michael addition and free radical photopolymerization (Article de journal) Journal of Photochemistry and Photobiology A-chemistry, 404 , p. 112959, 2021. @article{Gencoglu2021, title = {Photoinitiating systems based on poly(ethylene imine) for Michael addition and free radical photopolymerization}, author = { Turkan Gencoglu and Tugce Nur Eren and Jacques Lalevee and Duygu Avci}, doi = {10.1016/j.jphotochem.2020.112959}, year = {2021}, date = {2021-01-01}, journal = {Journal of Photochemistry and Photobiology A-chemistry}, volume = {404}, pages = {112959}, abstract = {Multifunctional polymeric photoinitiators with the ability of aza-Michael addition with acrylates, free radical polymerization of (meth)acrylates through type II photoinitiation and charge transfer complex (CTC) formation with iodonium salt (Iod) were prepared. They were synthesized via aza-Michael addition reaction between branched poly(ethylene imine) (PEI}, keywords = {}, pubstate = {published}, tppubtype = {article} } Multifunctional polymeric photoinitiators with the ability of aza-Michael addition with acrylates, free radical polymerization of (meth)acrylates through type II photoinitiation and charge transfer complex (CTC) formation with iodonium salt (Iod) were prepared. They were synthesized via aza-Michael addition reaction between branched poly(ethylene imine) (PEI |
Renkert, S; Fall, S; Motamen, S; Jarrosson, Th; Serein-Spirau, F; Heiser, Th; Simon, L; Reiter, G; Bubendorff, J L A new growth process for crystalline ultra-thin layers of conjugated oligomers used in field-effect transistor applications (Article de journal) Applied Surface Science, 539 , p. 148024, 2021. @article{Renkert2021, title = {A new growth process for crystalline ultra-thin layers of conjugated oligomers used in field-effect transistor applications}, author = { S. Renkert and S. Fall and S. Motamen and Th Jarrosson and F. Serein-Spirau and Th Heiser and L. Simon and G. Reiter and J. L. Bubendorff}, doi = {10.1016/j.apsusc.2020.148024}, year = {2021}, date = {2021-01-01}, journal = {Applied Surface Science}, volume = {539}, pages = {148024}, abstract = {Most organic semiconductor materials dewet on silicon wafers with thermal oxide layers. While Si-wafers represent convenient substrates for building a field effect transistor (FET), dewetting largely destroys the possibility for obtaining a compact and continuous crystalline thin organic semiconductor film and thus limits the mobility in these systems. Using oligothiophenes, we present an approach where the initial dewetting process can be turned into an advantage for generating very thin but large crystalline domains of a size up to the millimetres with all molecules sharing a single orientation. Our approach can be easily extended to other molecules, which have strongly differing growth velocities in the various directions of the crystal, for example due to directional pi-stacking interactions. FETs devices based on such large crystalline domains showed charge carrier mobilities that were two orders of magnitude higher compared to non-crystallized films.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Most organic semiconductor materials dewet on silicon wafers with thermal oxide layers. While Si-wafers represent convenient substrates for building a field effect transistor (FET), dewetting largely destroys the possibility for obtaining a compact and continuous crystalline thin organic semiconductor film and thus limits the mobility in these systems. Using oligothiophenes, we present an approach where the initial dewetting process can be turned into an advantage for generating very thin but large crystalline domains of a size up to the millimetres with all molecules sharing a single orientation. Our approach can be easily extended to other molecules, which have strongly differing growth velocities in the various directions of the crystal, for example due to directional pi-stacking interactions. FETs devices based on such large crystalline domains showed charge carrier mobilities that were two orders of magnitude higher compared to non-crystallized films. |
2020 |
Gibot, Pierre; Vidal, Loic; Laffont, Lydia; Mory, Julien Zirconia nanopowder synthesis via detonation of trinitrotoluene (Article de journal) Ceramics International, 46 (17), p. 27057–27062, 2020. @article{Gibot2020, title = {Zirconia nanopowder synthesis via detonation of trinitrotoluene}, author = { Pierre Gibot and Loic Vidal and Lydia Laffont and Julien Mory}, doi = {10.1016/j.ceramint.2020.07.182}, year = {2020}, date = {2020-12-01}, journal = {Ceramics International}, volume = {46}, number = {17}, pages = {27057--27062}, abstract = {Zirconium (IV) oxide nanopowder was successfully synthesized through the detonation of a mixture composed of 2,4,6 trinitrotoluene (TNT, C7H5N3O6) and zirconium sulfate tetrahydrate (Zr(SO4)(2)center dot 4H(2)O) as the energetic material and ceramic precursor, respectively. TNT, one of the most popular explosives, is a secondary energetic molecule and exhibits high stability and low sensitivity toward external stresses, making its handling safe. After detonation of the energetic material/ceramic precursor mixture and purification of the detonation soot, a crystallized zirconium oxide (ZrO2) powder composed of nanosized particles with a spherical morphology was produced and analysed by the usual characterization techniques (X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and nitrogen physisorption). The reaction mechanism, considering the thermochemical aspect of the explosive, is offered. This approach could provide promising opportunities for the synthesis of various nano-sized oxide ceramic powders.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Zirconium (IV) oxide nanopowder was successfully synthesized through the detonation of a mixture composed of 2,4,6 trinitrotoluene (TNT, C7H5N3O6) and zirconium sulfate tetrahydrate (Zr(SO4)(2)center dot 4H(2)O) as the energetic material and ceramic precursor, respectively. TNT, one of the most popular explosives, is a secondary energetic molecule and exhibits high stability and low sensitivity toward external stresses, making its handling safe. After detonation of the energetic material/ceramic precursor mixture and purification of the detonation soot, a crystallized zirconium oxide (ZrO2) powder composed of nanosized particles with a spherical morphology was produced and analysed by the usual characterization techniques (X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and nitrogen physisorption). The reaction mechanism, considering the thermochemical aspect of the explosive, is offered. This approach could provide promising opportunities for the synthesis of various nano-sized oxide ceramic powders. |
Mau, Alexandre; Le, Thi Huong; Dietlin, Celine; Bui, Thanh-Tuan; Graff, Bernadette; Dumur, Frederic; Goubard, Fabrice; Lalevee, Jacques Donor-acceptor-donor structured thioxanthone derivatives as visible photoinitiators (Article de journal) Polymer Chemistry, 11 (45), p. 7221–7234, 2020. @article{Mau2020, title = {Donor-acceptor-donor structured thioxanthone derivatives as visible photoinitiators}, author = { Alexandre Mau and Thi Huong Le and Celine Dietlin and Thanh-Tuan Bui and Bernadette Graff and Frederic Dumur and Fabrice Goubard and Jacques Lalevee}, doi = {10.1039/d0py01244k}, year = {2020}, date = {2020-12-01}, journal = {Polymer Chemistry}, volume = {11}, number = {45}, pages = {7221--7234}, abstract = {Three thioxanthone derivatives differing by their peripheral groups have been investigated as visible light photoinitiators of polymerisation. Their reactivity and efficiency have been compared with that of a commercial type II photoinitiator (2-isopropylthioxanthone - ITX) in the case of free radical polymerisation, cationic polymerisation and interpenetrated polymer networks synthesis for 25 mu m or 1.4 mm thick samples under 405 nm LED irradiation. They are incorporated into either, a two-component system with an iodonium salt or an amine, or a three-component system combining an iodonium salt and an amine. Using absorption and fluorescence spectroscopies, laser flash photolysis and molecular modelling, optical properties, excited state energies and lifetimes of these thioxanthone derivatives have been determined allowing a better understanding of the associated chemical mechanisms. Interestingly, the main reaction pathway for one of these thioxanthone derivatives in the photoinitiating systems was determined as involving its singlet state S-1 whereas ITX and thioxanthones are known to react from their triplet excited state T-1. The high efficiency of the new initiating systems was found as being worthwhile for laser write applications @405 nm but also for high migration stability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Three thioxanthone derivatives differing by their peripheral groups have been investigated as visible light photoinitiators of polymerisation. Their reactivity and efficiency have been compared with that of a commercial type II photoinitiator (2-isopropylthioxanthone - ITX) in the case of free radical polymerisation, cationic polymerisation and interpenetrated polymer networks synthesis for 25 mu m or 1.4 mm thick samples under 405 nm LED irradiation. They are incorporated into either, a two-component system with an iodonium salt or an amine, or a three-component system combining an iodonium salt and an amine. Using absorption and fluorescence spectroscopies, laser flash photolysis and molecular modelling, optical properties, excited state energies and lifetimes of these thioxanthone derivatives have been determined allowing a better understanding of the associated chemical mechanisms. Interestingly, the main reaction pathway for one of these thioxanthone derivatives in the photoinitiating systems was determined as involving its singlet state S-1 whereas ITX and thioxanthones are known to react from their triplet excited state T-1. The high efficiency of the new initiating systems was found as being worthwhile for laser write applications @405 nm but also for high migration stability. |
Breakspear, Steven; Ivanov, Dimitri A; Noecker, Bernd; Popescu, Crisan Nanomechanical properties of Monilethrix affected hair are independent of phenotype. (Article de journal) Journal of structural biology, 213 (1), p. 107679–107679, 2020. @article{Breakspear2020, title = {Nanomechanical properties of Monilethrix affected hair are independent of phenotype.}, author = { Steven Breakspear and Dimitri A. Ivanov and Bernd Noecker and Crisan Popescu}, doi = {10.1016/j.jsb.2020.107679}, year = {2020}, date = {2020-12-01}, journal = {Journal of structural biology}, volume = {213}, number = {1}, pages = {107679--107679}, abstract = {Utilising the AFM nanoindentation technique for the study of hair cross- and longitudinal sections, the mechanical anisotropy of human hair fibres affected by a rare congenital condition, Monilethrix, has been investigated for the first time. Supported by X-ray microdiffraction data, and applying a model based on an ideal composite material consisting of rods (KIFs) and matrix (KAPs) to Monilethrix affected fibres, it has been shown that the results could be grouped into clearly different classes, namely: almost isotropic behaviour for Monilethrix affected hairs and anisotropic behaviour for Control hair. Moreover, AFM nanoindentation of hair cross sections has demonstrated, also for the first time that hairs affected by Monilethrix have a continuous, and not periodic, weakness within the cortex. This has been attributed to disruptions in the KIF-KIF, KIF-intermacrofibrillar matrix or KIF-desmosome complexes within the hair shaft, as suggested by X-ray microdiffraction examination. Hairs from a patient exhibiting no obvious phenotype exhibited similar mechanical weakness despite the otherwise normal visual appearance of the fibre. This further supports a hypothesis that the beaded appearance of Monilethrix hair is a secondary factor, unrelated to the inherent structural weakness.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Utilising the AFM nanoindentation technique for the study of hair cross- and longitudinal sections, the mechanical anisotropy of human hair fibres affected by a rare congenital condition, Monilethrix, has been investigated for the first time. Supported by X-ray microdiffraction data, and applying a model based on an ideal composite material consisting of rods (KIFs) and matrix (KAPs) to Monilethrix affected fibres, it has been shown that the results could be grouped into clearly different classes, namely: almost isotropic behaviour for Monilethrix affected hairs and anisotropic behaviour for Control hair. Moreover, AFM nanoindentation of hair cross sections has demonstrated, also for the first time that hairs affected by Monilethrix have a continuous, and not periodic, weakness within the cortex. This has been attributed to disruptions in the KIF-KIF, KIF-intermacrofibrillar matrix or KIF-desmosome complexes within the hair shaft, as suggested by X-ray microdiffraction examination. Hairs from a patient exhibiting no obvious phenotype exhibited similar mechanical weakness despite the otherwise normal visual appearance of the fibre. This further supports a hypothesis that the beaded appearance of Monilethrix hair is a secondary factor, unrelated to the inherent structural weakness. |
Dahou, Tilia; Defoort, Francoise; Jeguirim, Mejdi; Dupont, Capucine Towards understanding the role of K during biomass steam gasification (Article de journal) Fuel, 282 , p. 118806, 2020. @article{Dahou2020a, title = {Towards understanding the role of K during biomass steam gasification}, author = { Tilia Dahou and Francoise Defoort and Mejdi Jeguirim and Capucine Dupont}, doi = {10.1016/j.fuel.2020.118806}, year = {2020}, date = {2020-12-01}, journal = {Fuel}, volume = {282}, pages = {118806}, abstract = {Steam gasification is known to be catalyzed by K. However, the exact mechanisms are not identified to this day. In the present study, the catalytic influence of K on biomass steam gasification and its interaction with Si was investigated. The study was conducted through thermogravimetric analysis (TGA) on rice husks as a Si-rich biomass and K2CO3 as a model K-compound. Experiments were conducted in three different configurations: biomass or inorganic compound alone; mixtures of biomass and inorganic powders; biomass and inorganic compound without contact in a two-compartment crucible. It was shown that K has a catalytic effect on both the pyrolysis and the gasification steps. These effects occur even when the K-compound is not in direct contact with the biomass. Therefore, it demonstrates that the mechanisms involve the gas phase through the volatilization of a K-compound, most likely KOH(g). However, the observed catalytic effect on rice husks was weaker than the effect obtained in the case of beech wood, a Si-poor and more generally ash-poor biomass, under the same conditions. It shows that there is a competition between i) the influence of K on the biomass pyrolysis and char gasification kinetics and ii) the interaction of K with SiO2 inherent to the biomass.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Steam gasification is known to be catalyzed by K. However, the exact mechanisms are not identified to this day. In the present study, the catalytic influence of K on biomass steam gasification and its interaction with Si was investigated. The study was conducted through thermogravimetric analysis (TGA) on rice husks as a Si-rich biomass and K2CO3 as a model K-compound. Experiments were conducted in three different configurations: biomass or inorganic compound alone; mixtures of biomass and inorganic powders; biomass and inorganic compound without contact in a two-compartment crucible. It was shown that K has a catalytic effect on both the pyrolysis and the gasification steps. These effects occur even when the K-compound is not in direct contact with the biomass. Therefore, it demonstrates that the mechanisms involve the gas phase through the volatilization of a K-compound, most likely KOH(g). However, the observed catalytic effect on rice husks was weaker than the effect obtained in the case of beech wood, a Si-poor and more generally ash-poor biomass, under the same conditions. It shows that there is a competition between i) the influence of K on the biomass pyrolysis and char gasification kinetics and ii) the interaction of K with SiO2 inherent to the biomass. |
Sukhawipat, Nathapong; Saetung, Nitinart; Pasetto, Pamela; Pilard, Jean-Francois; Bistac, Sophie; Saetung, Anuwat A novel high adhesion cationic waterborne polyurethane for green coating applications (Article de journal) Progress in Organic Coatings, 148 , p. 105854, 2020. @article{Sukhawipat2020, title = {A novel high adhesion cationic waterborne polyurethane for green coating applications}, author = { Nathapong Sukhawipat and Nitinart Saetung and Pamela Pasetto and Jean-Francois Pilard and Sophie Bistac and Anuwat Saetung}, doi = {10.1016/j.porgcoat.2020.105854}, year = {2020}, date = {2020-11-01}, journal = {Progress in Organic Coatings}, volume = {148}, pages = {105854}, abstract = {This report is the first one on a cationic waterborne polyurethane (cWPU) latex based on epoxidized hydroxyl telechelic natural rubber (eHTNR) polyol, providing potential for use as a coating made of renewable resources. A cWPU latex was synthesized by step growth emulsion polymerization from hydroxyl telechelic natural rubber (HTNR with M-n = 3000 g.mol(-1)) with fixed N-methyl diethanol amine content of 5.6 wt% and 2,4-toluene diisocyanate (NCO index = 100). The effects of proportion of epoxide units on HTNR polyol from 0 to 30 % on preparing cWPU latex were investigated. Chemical structures of HTNR and eHTNR polyol were confirmed by H-1-NMR spectroscopy. The resulting HTNR and eHTNR polyols present a unimodal size exclusion chromatography trace. The viscosity increased with epoxide fraction. The synthesized cWPU latex based on eHTNR was a stable milky-blue emulsion with well-defined size dispersion. All cWPU-eHTNR films showed good wettability, good chemical resistance, and high thermal stability, improving with the proportion of epoxide units. The mechanical properties of cWPU-eHTNR films were studied from their stress-strain curves. Moreover, the electrical properties were investigated. The cWPU-eHTNR films showed relatively low conductivity. Wettability, chemical resistance, adhesion, thermal stability, and electrical properties of cWPU-HTNR films improved with the proportion of epoxide units on the HTNR polyol. These results demonstrate a new synthesis route to develop cWPU latex based on a biosource, for coating applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This report is the first one on a cationic waterborne polyurethane (cWPU) latex based on epoxidized hydroxyl telechelic natural rubber (eHTNR) polyol, providing potential for use as a coating made of renewable resources. A cWPU latex was synthesized by step growth emulsion polymerization from hydroxyl telechelic natural rubber (HTNR with M-n = 3000 g.mol(-1)) with fixed N-methyl diethanol amine content of 5.6 wt% and 2,4-toluene diisocyanate (NCO index = 100). The effects of proportion of epoxide units on HTNR polyol from 0 to 30 % on preparing cWPU latex were investigated. Chemical structures of HTNR and eHTNR polyol were confirmed by H-1-NMR spectroscopy. The resulting HTNR and eHTNR polyols present a unimodal size exclusion chromatography trace. The viscosity increased with epoxide fraction. The synthesized cWPU latex based on eHTNR was a stable milky-blue emulsion with well-defined size dispersion. All cWPU-eHTNR films showed good wettability, good chemical resistance, and high thermal stability, improving with the proportion of epoxide units. The mechanical properties of cWPU-eHTNR films were studied from their stress-strain curves. Moreover, the electrical properties were investigated. The cWPU-eHTNR films showed relatively low conductivity. Wettability, chemical resistance, adhesion, thermal stability, and electrical properties of cWPU-HTNR films improved with the proportion of epoxide units on the HTNR polyol. These results demonstrate a new synthesis route to develop cWPU latex based on a biosource, for coating applications. |
Pimentel, Carlos; Mougin, Karine; Gnecco, Enrico; Pina, Carlos M Formation of zabuyelite, Li2CO3 , on dolomite and kutnohorite 10.4 surfaces from supersaturated and undersaturated solutions: Growth behavior and anomalous friction at the nanoscale (Article de journal) Journal of Crystal Growth, 550 , p. 125892, 2020. @article{Pimentel2020, title = {Formation of zabuyelite, Li2CO3 , on dolomite and kutnohorite 10.4 surfaces from supersaturated and undersaturated solutions: Growth behavior and anomalous friction at the nanoscale}, author = { Carlos Pimentel and Karine Mougin and Enrico Gnecco and Carlos M. Pina}, doi = {10.1016/j.jcrysgro.2020.125892}, year = {2020}, date = {2020-11-01}, journal = {Journal of Crystal Growth}, volume = {550}, pages = {125892}, abstract = {Cleaved dolomite (CaMg(CO3)(2)) crystals were immersed in supersaturated, saturated, and undersaturated solutions with respect to zabuyelite (Li2CO3), and the growth process was characterized using atomic force microscopy (AFM) and scanning electron microscopy (SEM). In all cases, overgrowths formed by 2D-nucleation could be clearly distinguished in the lateral force images recorded by AFM. With highly supersaturated solutions, AFM imaging was hindered by the formation of 3D crystal aggregates. When saturated solutions were used, the overgrowths reproduce the topography of the substrates, indicating that the lattice of the overgrown phase undergoes a compressive strain. Furthermore, we performed a nanotribological characterization by sliding a nanotip over both the 2D-overgrowths and dolomite substrates. Thus, friction coefficients, ti, could be easily quantified. As a result, a mu = 0.08 on the 2D-overgrowths was measured, which is one order of magnitude lower than the value of mu = 0.89 on the dolomite substrate. This friction reduction in the sliding of a nanotip on the overgrowth as compared to the friction observed on the dolomite substrate, together with the fact that atomicscale stick-slip is observed on dolomite but not on the 2D overgrowths, point towards an anomalously weak interaction of Li2CO3 overgrowths with the AFM probe.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cleaved dolomite (CaMg(CO3)(2)) crystals were immersed in supersaturated, saturated, and undersaturated solutions with respect to zabuyelite (Li2CO3), and the growth process was characterized using atomic force microscopy (AFM) and scanning electron microscopy (SEM). In all cases, overgrowths formed by 2D-nucleation could be clearly distinguished in the lateral force images recorded by AFM. With highly supersaturated solutions, AFM imaging was hindered by the formation of 3D crystal aggregates. When saturated solutions were used, the overgrowths reproduce the topography of the substrates, indicating that the lattice of the overgrown phase undergoes a compressive strain. Furthermore, we performed a nanotribological characterization by sliding a nanotip over both the 2D-overgrowths and dolomite substrates. Thus, friction coefficients, ti, could be easily quantified. As a result, a mu = 0.08 on the 2D-overgrowths was measured, which is one order of magnitude lower than the value of mu = 0.89 on the dolomite substrate. This friction reduction in the sliding of a nanotip on the overgrowth as compared to the friction observed on the dolomite substrate, together with the fact that atomicscale stick-slip is observed on dolomite but not on the 2D overgrowths, point towards an anomalously weak interaction of Li2CO3 overgrowths with the AFM probe. |
Largo, Fadwa; Haounati, Redouane; Akhouairi, Siham; Ouachtak, Hassan; Haouti, Rachid El; Guerdaoui, Anouar El; Hafid, Naima; Santos, Diogo M F; Akbal, Feryal; Kuleyin, Ayse; Jada, Amane; Addi, Abdelaziz Ait Adsorptive removal of both cationic and anionic dyes by using sepiolite clay mineral as adsorbent: Experimental and molecular dynamic simulation studies (Article de journal) Journal of Molecular Liquids, 318 , p. 114247, 2020. @article{Largo2020, title = {Adsorptive removal of both cationic and anionic dyes by using sepiolite clay mineral as adsorbent: Experimental and molecular dynamic simulation studies}, author = { Fadwa Largo and Redouane Haounati and Siham Akhouairi and Hassan Ouachtak and Rachid El Haouti and Anouar El Guerdaoui and Naima Hafid and Diogo M. F. Santos and Feryal Akbal and Ayse Kuleyin and Amane Jada and Abdelaziz Ait Addi}, doi = {10.1016/j.molliq.2020.114247}, year = {2020}, date = {2020-11-01}, journal = {Journal of Molecular Liquids}, volume = {318}, pages = {114247}, abstract = {In the present work, sepiolite clay was assessed as an adsorbent for the removal of cationic (Methylene Blue: MB) and anionic (Direct Red-23: DR-23) dyes from aqueous media. Firstly, the sepiolite clay mineral was characterized using different instrumental techniques viz., XRD, SEM, EDX, FIR, X-ray Fluorescence, and BET analysis. Thereafter, the adsorption study was examined as a function of the adsorbent amount, the contact time, the aqueous phase pH, the ionic strength, and the initial dye amount. The data indicate that the adsorption was a function of the pH with high adsorption amounts of MB and DR-23, in basic and acidic, respectively, pH ranges. By comparing experimental data to the Langmuir predictions, the calculated maximum dye adsorbed amounts were 124.9 and 649.37 mg g(-1), for MB and DR-23, respectively. Further, kinetic adsorption studies have shown that adsorption of MB and DR-23 from aqueous media onto the sepiolite follow, respectively, the pseudo-second order and the pseudo first-order kinetic models. On the other hand, Molecular Dynamic (MD) simulations were performed to shed light on the pH-effect on the adsorptive properties of the sepiolite clay surface and the adsorption behavior of both hazardous MB and DR-23 dyes into the adsorbent surface. The better affinity of the MB molecules toward the sepiolite in the basic media could be related to the dispersion forces and electrostatic interactions. On the other hand, the DR-23 molecules show more favorable interaction in the acidic media as a result of the hydrogen bonds formed between the dye molecule and the sepiolite surface oxygen atoms. In addition, the negative values of interaction energies calculated show that the adsorption processes of both hazardous MB and DR-23 molecules on the sepiolite surface are spontaneous, which is in good agreement with the results observed experimentally. (C) 2020 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the present work, sepiolite clay was assessed as an adsorbent for the removal of cationic (Methylene Blue: MB) and anionic (Direct Red-23: DR-23) dyes from aqueous media. Firstly, the sepiolite clay mineral was characterized using different instrumental techniques viz., XRD, SEM, EDX, FIR, X-ray Fluorescence, and BET analysis. Thereafter, the adsorption study was examined as a function of the adsorbent amount, the contact time, the aqueous phase pH, the ionic strength, and the initial dye amount. The data indicate that the adsorption was a function of the pH with high adsorption amounts of MB and DR-23, in basic and acidic, respectively, pH ranges. By comparing experimental data to the Langmuir predictions, the calculated maximum dye adsorbed amounts were 124.9 and 649.37 mg g(-1), for MB and DR-23, respectively. Further, kinetic adsorption studies have shown that adsorption of MB and DR-23 from aqueous media onto the sepiolite follow, respectively, the pseudo-second order and the pseudo first-order kinetic models. On the other hand, Molecular Dynamic (MD) simulations were performed to shed light on the pH-effect on the adsorptive properties of the sepiolite clay surface and the adsorption behavior of both hazardous MB and DR-23 dyes into the adsorbent surface. The better affinity of the MB molecules toward the sepiolite in the basic media could be related to the dispersion forces and electrostatic interactions. On the other hand, the DR-23 molecules show more favorable interaction in the acidic media as a result of the hydrogen bonds formed between the dye molecule and the sepiolite surface oxygen atoms. In addition, the negative values of interaction energies calculated show that the adsorption processes of both hazardous MB and DR-23 molecules on the sepiolite surface are spontaneous, which is in good agreement with the results observed experimentally. (C) 2020 Elsevier B.V. All rights reserved. |
Brunet, Sylvette; Lebeau, Benedicte; Naboulsi, Issam; Michelin, Laure; Comparot, Jean Dominique; Marichal, Claire; Rigolet, Severinne; Bonne, Magali; Blin, Jean-Luc Effect of Mesostructured Zirconia Support on the Activity and Selectivity of 4,6-Dimethydibenzothiophene Hydrodesulfurization (Article de journal) Catalysts, 10 (10), p. 1162, 2020. @article{Brunet2020, title = {Effect of Mesostructured Zirconia Support on the Activity and Selectivity of 4,6-Dimethydibenzothiophene Hydrodesulfurization}, author = { Sylvette Brunet and Benedicte Lebeau and Issam Naboulsi and Laure Michelin and Jean Dominique Comparot and Claire Marichal and Severinne Rigolet and Magali Bonne and Jean-Luc Blin}, doi = {10.3390/catal10101162}, year = {2020}, date = {2020-10-01}, journal = {Catalysts}, volume = {10}, number = {10}, pages = {1162}, abstract = {In contrast with the conventional CoMoS/alumina catalyst, the use of amorphous mesostructured ZrO2 as support for the dispersion of the CoMoS active phase in deep hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene led to a higher promotion rate and a better sulfidation of the cobalt species. The CoMoS, dispersed over mesostructured amorphous ZrO2 as catalyst, also induced a modification of the main desulfurization way; in this case, a shift towards direct desulfurization selectivity was observed. This result was unexpected regarding the literature. Indeed, the hydrogenated route was observed for commercial zirconia. The designed catalysts are therefore more eco-friendly, since they consume less hydrogen. This implies a better use of the fossil resources.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In contrast with the conventional CoMoS/alumina catalyst, the use of amorphous mesostructured ZrO2 as support for the dispersion of the CoMoS active phase in deep hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene led to a higher promotion rate and a better sulfidation of the cobalt species. The CoMoS, dispersed over mesostructured amorphous ZrO2 as catalyst, also induced a modification of the main desulfurization way; in this case, a shift towards direct desulfurization selectivity was observed. This result was unexpected regarding the literature. Indeed, the hydrogenated route was observed for commercial zirconia. The designed catalysts are therefore more eco-friendly, since they consume less hydrogen. This implies a better use of the fossil resources. |
Sun, Ke; Liu, Shaohui; Pigot, Corentin; Brunel, Damien; Graff, Bernadette; Nechab, Malek; Gigmes, Didier; Morlet-Savary, Fabrice; Zhang, Yijun; Xiao, Pu; Dumur, Frederic; Lalevee, Jacques Catalysts, 10 (10), p. 1196, 2020. @article{Sun2020a, title = {Novel Push-Pull Dyes Derived from 1H-cyclopenta[b]naphthalene-1,3(2H)-dione as Versatile Photoinitiators for Photopolymerization and Their Related Applications: 3D Printing and Fabrication of Photocomposites}, author = { Ke Sun and Shaohui Liu and Corentin Pigot and Damien Brunel and Bernadette Graff and Malek Nechab and Didier Gigmes and Fabrice Morlet-Savary and Yijun Zhang and Pu Xiao and Frederic Dumur and Jacques Lalevee}, doi = {10.3390/catal10101196}, year = {2020}, date = {2020-10-01}, journal = {Catalysts}, volume = {10}, number = {10}, pages = {1196}, abstract = {A series of eleven push-pull chromophores with specific structures have been designed for the free radical polymerization of acrylates, but also for the fabrication of photocomposites and 3D-printed structures. New photoinitiating systems comprising the different push-pull dyes showed excellent photochemical reactivities at 405 nm. Notably, polymerization reactions could be initiated with light-emitting diodes (LEDs) which constitute a unique opportunity to promote the free radical polymerization under mild conditions, i.e., low light intensity (e.g., sunlight) and under air. Photopolymerization is an active research field, and push-pull dyes have already been investigated for this purpose. Besides, it remains of crucial interest to investigate new reactive structures capable of efficiently initiating photopolymerization reactions. The plausible potential of these structures to act as efficient photoinitiators in vat photopolymerization (or 3D printing) and fabrication of photocomposites prompts us to select eleven new push-pull dyes to design multi-component photoinitiating systems activable with LEDs emitting at 405 nm. Precisely, a tertiary amine, i.e., ethyl dimethylaminobenzoate (EDB) used as an electron/hydrogen donor and an iodonium salt used as an electron acceptor were selected to behave as powerful co-initiators to construct three-component photoinitiating systems (PISs) with the different push-pull dyes. Among these new PISs, dye 8 and 9-based PISs could efficiently promote the free radical photopolymerization of acrylates upon exposure to a LED emitting at 405 nm also upon sunlight irradiation, highlighting their huge performance. Photoinitiating abilities could be explained on the basis of steady state photolysis experiments. Fluorescence measurements and electron spin resonance (ESR) spin-trapping experiments were also performed to obtain a deeper insight into the chemical mechanisms supporting the polymerization reaction and determine the way the initiating species, i.e., the radicals, are observed. Finally, two investigated dye-based PISs were applied to the fabrications of photocomposites. Three-dimensional patterns with excellent spatial resolutions were generated by the laser writing technique to identify the effects of photopolymerization of acrylates both in the absence and presence of fillers (silica). Interestingly, comparison between the 3D objects fabricated by the PISs/monomer systems and the PISs/monomer/filler photocomposites indicates that the newly designed photocomposites are suitable for practical applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A series of eleven push-pull chromophores with specific structures have been designed for the free radical polymerization of acrylates, but also for the fabrication of photocomposites and 3D-printed structures. New photoinitiating systems comprising the different push-pull dyes showed excellent photochemical reactivities at 405 nm. Notably, polymerization reactions could be initiated with light-emitting diodes (LEDs) which constitute a unique opportunity to promote the free radical polymerization under mild conditions, i.e., low light intensity (e.g., sunlight) and under air. Photopolymerization is an active research field, and push-pull dyes have already been investigated for this purpose. Besides, it remains of crucial interest to investigate new reactive structures capable of efficiently initiating photopolymerization reactions. The plausible potential of these structures to act as efficient photoinitiators in vat photopolymerization (or 3D printing) and fabrication of photocomposites prompts us to select eleven new push-pull dyes to design multi-component photoinitiating systems activable with LEDs emitting at 405 nm. Precisely, a tertiary amine, i.e., ethyl dimethylaminobenzoate (EDB) used as an electron/hydrogen donor and an iodonium salt used as an electron acceptor were selected to behave as powerful co-initiators to construct three-component photoinitiating systems (PISs) with the different push-pull dyes. Among these new PISs, dye 8 and 9-based PISs could efficiently promote the free radical photopolymerization of acrylates upon exposure to a LED emitting at 405 nm also upon sunlight irradiation, highlighting their huge performance. Photoinitiating abilities could be explained on the basis of steady state photolysis experiments. Fluorescence measurements and electron spin resonance (ESR) spin-trapping experiments were also performed to obtain a deeper insight into the chemical mechanisms supporting the polymerization reaction and determine the way the initiating species, i.e., the radicals, are observed. Finally, two investigated dye-based PISs were applied to the fabrications of photocomposites. Three-dimensional patterns with excellent spatial resolutions were generated by the laser writing technique to identify the effects of photopolymerization of acrylates both in the absence and presence of fillers (silica). Interestingly, comparison between the 3D objects fabricated by the PISs/monomer systems and the PISs/monomer/filler photocomposites indicates that the newly designed photocomposites are suitable for practical applications. |
Rahal, Mahmoud; Mokbel, Haifaa; Graff, Bernadette; Toufaily, Joumana; Hamieh, Tayssir; Dumur, Frederic; Lalevee, Jacques Mono vs. Difunctional Coumarin as Photoinitiators in Photocomposite Synthesis and 3D Printing (Article de journal) Catalysts, 10 (10), p. 1202, 2020. @article{Rahal2020a, title = {Mono vs. Difunctional Coumarin as Photoinitiators in Photocomposite Synthesis and 3D Printing}, author = { Mahmoud Rahal and Haifaa Mokbel and Bernadette Graff and Joumana Toufaily and Tayssir Hamieh and Frederic Dumur and Jacques Lalevee}, doi = {10.3390/catal10101202}, year = {2020}, date = {2020-10-01}, journal = {Catalysts}, volume = {10}, number = {10}, pages = {1202}, abstract = {This work is devoted to investigate three coumarin derivatives (Coum1, Coum2, and Coum3), proposed as new photoinitiators of polymerization when combined with an additive, i.e., an iodonium salt, and used for the free radical polymerization (FRP) of acrylate monomers under mild irradiation conditions. The different coumarin derivatives can also be employed in three component photoinitiating systems with a Iod/amine (ethyl 4-dimethylaminobenzoate (EDB) or N-phenylglycine (NPG)) couple for FRP upon irradiation with an LED @ 405 nm. These compounds showed excellent photoinitiating abilities, and high polymerization rates and final conversions (FC) were obtained. The originality of this work relies on the comparison of the photoinitiating abilities of monofunctional (Coum1 and Coum2) vs. difunctional (Coum3) compounds. Coum3 is a combined structure of Coum1 and Coum2, leading to a sterically hindered chemical structure with a relatively high molecular weight. As a general rule, a high molecular weight should reduce the migration of initiating molecules and favor photochemical properties such as photobleaching of the final polymer. As attempted, from the efficiency point of view, Coum3 can initiate the FRP, but a low reactivity was observed compared to the monofunctional compound (Coum1 and Coum2). Indeed, to study the photochemical and photophysical properties of these compounds, different parameters were taken into account, e.g., the light absorption and emission properties, steady state photolysis, and fluorescence quenching. To examine these different points, several techniques were used including UV-visible spectroscopy, real-time Fourier Transform Infrared Spectroscopy (RT-FTIR), fluorescence spectroscopy, and cyclic voltammetry. The photochemical mechanism involved in the polymerization process is also detailed. The best coumarins investigated in this work were used for laser writing (3D printing) experiments and also for photocomposite synthesis containing glass fibers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work is devoted to investigate three coumarin derivatives (Coum1, Coum2, and Coum3), proposed as new photoinitiators of polymerization when combined with an additive, i.e., an iodonium salt, and used for the free radical polymerization (FRP) of acrylate monomers under mild irradiation conditions. The different coumarin derivatives can also be employed in three component photoinitiating systems with a Iod/amine (ethyl 4-dimethylaminobenzoate (EDB) or N-phenylglycine (NPG)) couple for FRP upon irradiation with an LED @ 405 nm. These compounds showed excellent photoinitiating abilities, and high polymerization rates and final conversions (FC) were obtained. The originality of this work relies on the comparison of the photoinitiating abilities of monofunctional (Coum1 and Coum2) vs. difunctional (Coum3) compounds. Coum3 is a combined structure of Coum1 and Coum2, leading to a sterically hindered chemical structure with a relatively high molecular weight. As a general rule, a high molecular weight should reduce the migration of initiating molecules and favor photochemical properties such as photobleaching of the final polymer. As attempted, from the efficiency point of view, Coum3 can initiate the FRP, but a low reactivity was observed compared to the monofunctional compound (Coum1 and Coum2). Indeed, to study the photochemical and photophysical properties of these compounds, different parameters were taken into account, e.g., the light absorption and emission properties, steady state photolysis, and fluorescence quenching. To examine these different points, several techniques were used including UV-visible spectroscopy, real-time Fourier Transform Infrared Spectroscopy (RT-FTIR), fluorescence spectroscopy, and cyclic voltammetry. The photochemical mechanism involved in the polymerization process is also detailed. The best coumarins investigated in this work were used for laser writing (3D printing) experiments and also for photocomposite synthesis containing glass fibers. |
Frikha, Kawthar; Limousy, Lionel; Bouaziz, Jamel; Chaari, Kamel; Bennici, Simona Synthesis, Characterization and Catalytic Activity of Ternary Oxide Catalysts Using the Microwave-Assisted Solution Combustion Method (Article de journal) Materials, 13 (20), p. 4607, 2020. @article{Frikha2020a, title = {Synthesis, Characterization and Catalytic Activity of Ternary Oxide Catalysts Using the Microwave-Assisted Solution Combustion Method}, author = { Kawthar Frikha and Lionel Limousy and Jamel Bouaziz and Kamel Chaari and Simona Bennici}, doi = {10.3390/ma13204607}, year = {2020}, date = {2020-10-01}, journal = {Materials}, volume = {13}, number = {20}, pages = {4607}, abstract = {Ni-Co-Al, Ni-Cu-Al and Co-Cu-Al ternary oxide catalysts, with a fixed 5 wt% transition metal loading, were prepared by the microwave-assisted solution combustion method and tested in CO oxidation. The bulk and surface properties of the catalysts were investigated, using XRD, N-2 adsorption-desorption, SEM, XPS and TEM techniques. XRD, XPS and TEM results revealed that nickel and cobalt were present as spinels on the surface and in the bulk. Differently, copper was preferentially present in "bulk-like" CuO-segregated phases. No interaction between the couples of transition metal species was detected, and the introduction of Cu-containing precursors into the Ni-Al or Co-Al combustion systems was not effective in preventing the formation of NiAl2O4 and CoAl2O4 spinels in the Ni- or Co-containing catalysts. Copper-containing catalysts were the most active, indicating that copper oxides are the effective active species for improving the CO oxidation activity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Ni-Co-Al, Ni-Cu-Al and Co-Cu-Al ternary oxide catalysts, with a fixed 5 wt% transition metal loading, were prepared by the microwave-assisted solution combustion method and tested in CO oxidation. The bulk and surface properties of the catalysts were investigated, using XRD, N-2 adsorption-desorption, SEM, XPS and TEM techniques. XRD, XPS and TEM results revealed that nickel and cobalt were present as spinels on the surface and in the bulk. Differently, copper was preferentially present in "bulk-like" CuO-segregated phases. No interaction between the couples of transition metal species was detected, and the introduction of Cu-containing precursors into the Ni-Al or Co-Al combustion systems was not effective in preventing the formation of NiAl2O4 and CoAl2O4 spinels in the Ni- or Co-containing catalysts. Copper-containing catalysts were the most active, indicating that copper oxides are the effective active species for improving the CO oxidation activity. |
Enneiymy, Mohamed; Fioux, Philippe; Drian, Claude Le; Ghimbeu, Camelia Matei; Becht, Jean-Michel Palladium nanoparticles embedded in mesoporous carbons as efficient, green and reusable catalysts for mild hydrogenations of nitroarenes (Article de journal) Rsc Advances, 10 (60), p. 36741–36750, 2020. @article{Enneiymy2020, title = {Palladium nanoparticles embedded in mesoporous carbons as efficient, green and reusable catalysts for mild hydrogenations of nitroarenes}, author = { Mohamed Enneiymy and Philippe Fioux and Claude Le Drian and Camelia Matei Ghimbeu and Jean-Michel Becht}, doi = {10.1039/d0ra05713d}, year = {2020}, date = {2020-10-01}, journal = {Rsc Advances}, volume = {10}, number = {60}, pages = {36741--36750}, abstract = {The reduction of nitroarenes is the most efficient route for the preparation of aromatic primary amines. These reductions are generally performed in the presence of heterogeneous transition metal catalysts, which are rather efficient but long and tedious to prepare. In addition, they contain very expensive metals that are in most cases difficult to reuse. Therefore, the development of efficient, easily accessible and reusable Pd catalysts obtained rapidly from safe and non-toxic starting materials was implemented in this report. Two bottom-up synthesis methods were used, the first consisted in the impregnation of a micro/mesoporous carbon support with a Pd salt solution, followed by thermal reduction (at 300, 450 or 600 degrees C) while the second involved a direct synthesis based on the co-assembly and pyrolysis (600 degrees C) of a mixture of a phenolic precursor, glyoxal, a surfactant and a Pd salt. The obtained composites possess Pd nanoparticles (NPs) of tunable sizes (ranging from 1-2 to 7.0 nm) and homogeneously distributed in the carbon framework (pores/walls). It turned out that they were successfully used for mild and environment-friendly hydrogenations of nitroarenes at room temperature under H-2(1 atm) in EtOH in the presence of only 5 mequiv. of supported Pd. The determinations of the optimal characteristics of the catalysts constituted a second objective of this study. It was found that the activity of the catalysts was strongly dependent on the Pd NPs sizes,i.e., catalysts bearing small Pd NPs (1.2 nm obtained at 300 degrees C and 3.4 nm obtained at 450 degrees C) exhibited an excellent activity, while those containing larger Pd NPs (6.4 nm and 7.0 nm obtained at 600 degrees C, either by indirect or direct methods) were not active. Moreover, the possibility to reuse the catalysts was shown to be dependent on the surface chemistry of the Pd NPs: the smallest Pd NPs are prone to oxidation by air and their surface was gradually covered by a PdO shell decreasing their activity during reuse. A good compromise between intrinsic catalytic activity (i.e. during first use) and possibility of reuse was found in the catalyst made by impregnation followed by reduction at 450 degrees C since the hydrogenation could be performed in only 2 h in EtOH or even in water. The catalyst was quantitatively recovered after reaction by filtration, used at least 7 times with no loss of efficiency. Advantageously, almost Pd-free primary aromatic amines were obtained since the Pd leaching was very low (<0.1% of the introduced amount). Compared to numerous reports from the literature, the catalysts described here were both easily accessible from eco-friendly precursors and very active for hydrogenations under mild and "green" reaction conditions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The reduction of nitroarenes is the most efficient route for the preparation of aromatic primary amines. These reductions are generally performed in the presence of heterogeneous transition metal catalysts, which are rather efficient but long and tedious to prepare. In addition, they contain very expensive metals that are in most cases difficult to reuse. Therefore, the development of efficient, easily accessible and reusable Pd catalysts obtained rapidly from safe and non-toxic starting materials was implemented in this report. Two bottom-up synthesis methods were used, the first consisted in the impregnation of a micro/mesoporous carbon support with a Pd salt solution, followed by thermal reduction (at 300, 450 or 600 degrees C) while the second involved a direct synthesis based on the co-assembly and pyrolysis (600 degrees C) of a mixture of a phenolic precursor, glyoxal, a surfactant and a Pd salt. The obtained composites possess Pd nanoparticles (NPs) of tunable sizes (ranging from 1-2 to 7.0 nm) and homogeneously distributed in the carbon framework (pores/walls). It turned out that they were successfully used for mild and environment-friendly hydrogenations of nitroarenes at room temperature under H-2(1 atm) in EtOH in the presence of only 5 mequiv. of supported Pd. The determinations of the optimal characteristics of the catalysts constituted a second objective of this study. It was found that the activity of the catalysts was strongly dependent on the Pd NPs sizes,i.e., catalysts bearing small Pd NPs (1.2 nm obtained at 300 degrees C and 3.4 nm obtained at 450 degrees C) exhibited an excellent activity, while those containing larger Pd NPs (6.4 nm and 7.0 nm obtained at 600 degrees C, either by indirect or direct methods) were not active. Moreover, the possibility to reuse the catalysts was shown to be dependent on the surface chemistry of the Pd NPs: the smallest Pd NPs are prone to oxidation by air and their surface was gradually covered by a PdO shell decreasing their activity during reuse. A good compromise between intrinsic catalytic activity (i.e. during first use) and possibility of reuse was found in the catalyst made by impregnation followed by reduction at 450 degrees C since the hydrogenation could be performed in only 2 h in EtOH or even in water. The catalyst was quantitatively recovered after reaction by filtration, used at least 7 times with no loss of efficiency. Advantageously, almost Pd-free primary aromatic amines were obtained since the Pd leaching was very low (<0.1% of the introduced amount). Compared to numerous reports from the literature, the catalysts described here were both easily accessible from eco-friendly precursors and very active for hydrogenations under mild and "green" reaction conditions. |
Noirbent, Guillaume; Xu, Yangyang; Bonardi, Aude-Heloise; Gigmes, Didier; Lalevee, Jacques; Dumur, Frederic Metalated porphyrins as versatile visible light and NIR photoinitiators of polymerization (Article de journal) European Polymer Journal, 139 , p. 110019, 2020. @article{Noirbent2020a, title = {Metalated porphyrins as versatile visible light and NIR photoinitiators of polymerization}, author = { Guillaume Noirbent and Yangyang Xu and Aude-Heloise Bonardi and Didier Gigmes and Jacques Lalevee and Frederic Dumur}, doi = {10.1016/j.eurpolymj.2020.110019}, year = {2020}, date = {2020-10-01}, journal = {European Polymer Journal}, volume = {139}, pages = {110019}, abstract = {A series of metalated porphyrins has been prepared and used as visible light photoinitiators of polymerization activable under low light intensity. Among the six metalated porphyrins examined in this work, five of them have never been reported in the literature and specifically designed to exhibit a good solubility in monomers. Three of the proposed structures were efficient @405 nm but remarkably, despites their weak absorptions at 785 nm, efficient Near Infrared (NIR) polymerization profiles could also be obtained during the free radical polymerization of a methacrylate resin. To support the experimental observation of a polymerization process, a mechanism has been proposed based on combined photochemical and photothermal pathways.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A series of metalated porphyrins has been prepared and used as visible light photoinitiators of polymerization activable under low light intensity. Among the six metalated porphyrins examined in this work, five of them have never been reported in the literature and specifically designed to exhibit a good solubility in monomers. Three of the proposed structures were efficient @405 nm but remarkably, despites their weak absorptions at 785 nm, efficient Near Infrared (NIR) polymerization profiles could also be obtained during the free radical polymerization of a methacrylate resin. To support the experimental observation of a polymerization process, a mechanism has been proposed based on combined photochemical and photothermal pathways. |
Wittmann, Bernd; Wiesneth, Stephan; Motamen, Sajedeh; Simon, Laurent; Serein-Spirau, Francoise; Reiter, Guenter; Hildner, Richard Energy transport and light propagation mechanisms in organic single crystals (Article de journal) Journal of Chemical Physics, 153 (14), p. 144202, 2020. @article{Wittmann2020, title = {Energy transport and light propagation mechanisms in organic single crystals}, author = { Bernd Wittmann and Stephan Wiesneth and Sajedeh Motamen and Laurent Simon and Francoise Serein-Spirau and Guenter Reiter and Richard Hildner}, doi = {10.1063/5.0019832}, year = {2020}, date = {2020-10-01}, journal = {Journal of Chemical Physics}, volume = {153}, number = {14}, pages = {144202}, abstract = {Unambiguous information about spatiotemporal exciton dynamics in three-dimensional nanometer- to micrometer-sized organic structures is difficult to obtain experimentally. Exciton dynamics can be modified by annihilation processes, and different light propagation mechanisms can take place, such as active waveguiding and photon recycling. Since these various processes and mechanisms can lead to similar spectroscopic and microscopic signatures on comparable time scales, their discrimination is highly demanding. Here, we study individual organic single crystals grown from thiophene-based oligomers. We use time-resolved detection-beam scanning microscopy to excite a local singlet exciton population and monitor the subsequent broadening of the photoluminescence (PL) signal in space and on pico- to nanosecond time scales. Combined with Monte Carlo simulations, we were able to exclude photon recycling for our system, whereas leakage radiation upon active waveguiding leads to an apparent PL broadening of about 20% compared to the initial excitation profile. Exciton-exciton annihilation becomes important at high excitation fluence and apparently accelerates the exciton dynamics leading to apparently increased diffusion lengths. At low excitation fluences, the spatiotemporal PL broadening results from singlet exciton diffusion with diffusion lengths of up to 210 nm. Surprisingly, even in structurally highly ordered single crystals, the transport dynamics is subdiffusive and shows variations between different crystals, which we relate to varying degrees of static and dynamic electronic disorders.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Unambiguous information about spatiotemporal exciton dynamics in three-dimensional nanometer- to micrometer-sized organic structures is difficult to obtain experimentally. Exciton dynamics can be modified by annihilation processes, and different light propagation mechanisms can take place, such as active waveguiding and photon recycling. Since these various processes and mechanisms can lead to similar spectroscopic and microscopic signatures on comparable time scales, their discrimination is highly demanding. Here, we study individual organic single crystals grown from thiophene-based oligomers. We use time-resolved detection-beam scanning microscopy to excite a local singlet exciton population and monitor the subsequent broadening of the photoluminescence (PL) signal in space and on pico- to nanosecond time scales. Combined with Monte Carlo simulations, we were able to exclude photon recycling for our system, whereas leakage radiation upon active waveguiding leads to an apparent PL broadening of about 20% compared to the initial excitation profile. Exciton-exciton annihilation becomes important at high excitation fluence and apparently accelerates the exciton dynamics leading to apparently increased diffusion lengths. At low excitation fluences, the spatiotemporal PL broadening results from singlet exciton diffusion with diffusion lengths of up to 210 nm. Surprisingly, even in structurally highly ordered single crystals, the transport dynamics is subdiffusive and shows variations between different crystals, which we relate to varying degrees of static and dynamic electronic disorders. |
de Matos, Caroline Silva; Ghimbeu, Camelia Matei; Brendle, Jocelyne; Limousy, Lionel; Constantino, Vera Regina Leopoldo Thermal decomposition of a layered double hydroxide as a bottom up approach for the synthesis of metallic nanoparticles embedded in carbon structures (Article de journal) New Journal of Chemistry, 44 (39), p. 16721–16732, 2020. @article{Matos2020, title = {Thermal decomposition of a layered double hydroxide as a bottom up approach for the synthesis of metallic nanoparticles embedded in carbon structures}, author = { Caroline Silva de Matos and Camelia Matei Ghimbeu and Jocelyne Brendle and Lionel Limousy and Vera Regina Leopoldo Constantino}, doi = {10.1039/d0nj01938k}, year = {2020}, date = {2020-10-01}, journal = {New Journal of Chemistry}, volume = {44}, number = {39}, pages = {16721--16732}, abstract = {In the present study, the thermal behaviour of a layered double hydroxide (LDH) intercalated with a carboxymethylcellulose (CMC) polymer was evaluated to inspect the effect of the temperature on the chemical processes that occur during its decomposition under a nitrogen atmosphere, ranging from 500 to 1000 degrees C, as well as the product properties. The intercalation compound (LDH-CMC) proved to be a suitable precursor to develop inorganic nanocomposites based on Ni metallic nanoparticles (Ni-MNPs) embedded in a carbonaceous matrix by a bottom-up strategy involving a carbothermal reaction. Considering the temperature effect on the LDH-CMC decomposition processes, as well as the dispersion of metallic and carbon sources at the nanoscale level favoured by the intercalated structure, the simple synthetic approach reported in this work permits fine tuning of the production of valuable phases. The nanocomposites with ordered carbonaceous structures and transition metallic nanoparticles are interesting functional materials for electrocatalysis.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the present study, the thermal behaviour of a layered double hydroxide (LDH) intercalated with a carboxymethylcellulose (CMC) polymer was evaluated to inspect the effect of the temperature on the chemical processes that occur during its decomposition under a nitrogen atmosphere, ranging from 500 to 1000 degrees C, as well as the product properties. The intercalation compound (LDH-CMC) proved to be a suitable precursor to develop inorganic nanocomposites based on Ni metallic nanoparticles (Ni-MNPs) embedded in a carbonaceous matrix by a bottom-up strategy involving a carbothermal reaction. Considering the temperature effect on the LDH-CMC decomposition processes, as well as the dispersion of metallic and carbon sources at the nanoscale level favoured by the intercalated structure, the simple synthetic approach reported in this work permits fine tuning of the production of valuable phases. The nanocomposites with ordered carbonaceous structures and transition metallic nanoparticles are interesting functional materials for electrocatalysis. |
Tar, Haja; Kashar, Tahani I; Kouki, Noura; Aldawas, Reema; Graff, Bernadette; Lalevee, Jacques Novel Copper Photoredox Catalysts for Polymerization: An In Situ Synthesis of Metal Nanoparticles. (Article de journal) Polymers, 12 (10), 2020. @article{Tar2020, title = {Novel Copper Photoredox Catalysts for Polymerization: An In Situ Synthesis of Metal Nanoparticles.}, author = { Haja Tar and Tahani I. Kashar and Noura Kouki and Reema Aldawas and Bernadette Graff and Jacques Lalevee}, doi = {10.3390/polym12102293}, year = {2020}, date = {2020-10-01}, journal = {Polymers}, volume = {12}, number = {10}, abstract = {The copper II complex (HLCuCl) carrying 2,4 dinitrophenylhydrazone (L) is synthesized and evaluated as a new photoredox catalyst/photoinitiator in combination with triethylamine (TEA) and iodonium salt (Iod) for the radical polymerization of ethylene glycol diacrylate during exposure to visible light using a photoreactor at 419 nm. The copper complex reactivity with TEA/Iod salt/gold chloride showed a good production and stability of gold nanoparticles. Finally, the high performance of Cu (II) complex for radical photopolymerization incorporating gold nanoparticles is provided. The photochemical mechanisms for the production of initiating radicals are studied using cyclic voltammetry. Polymer nanocomposites containing gold nanoparticles (Au NPs) in situ photogenerated during the irradiation process were prepared. The formation of Au NPs inside the polymer matrix was through UV-Vis and EDS/SEM analyses.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The copper II complex (HLCuCl) carrying 2,4 dinitrophenylhydrazone (L) is synthesized and evaluated as a new photoredox catalyst/photoinitiator in combination with triethylamine (TEA) and iodonium salt (Iod) for the radical polymerization of ethylene glycol diacrylate during exposure to visible light using a photoreactor at 419 nm. The copper complex reactivity with TEA/Iod salt/gold chloride showed a good production and stability of gold nanoparticles. Finally, the high performance of Cu (II) complex for radical photopolymerization incorporating gold nanoparticles is provided. The photochemical mechanisms for the production of initiating radicals are studied using cyclic voltammetry. Polymer nanocomposites containing gold nanoparticles (Au NPs) in situ photogenerated during the irradiation process were prepared. The formation of Au NPs inside the polymer matrix was through UV-Vis and EDS/SEM analyses. |
Cervantes-Martinez, Claudia Violeta; Stebe, Marie-Jose; Emo, Melanie; Lebeau, Benedicte; Blin, Jean-Luc Hierarchical mesoporous silica templated by the combination of fine emulsion and micelles (Article de journal) Microporous and Mesoporous Materials, 305 , p. 110376, 2020. @article{Cervantes-Martinez2020, title = {Hierarchical mesoporous silica templated by the combination of fine emulsion and micelles}, author = { Claudia Violeta Cervantes-Martinez and Marie-Jose Stebe and Melanie Emo and Benedicte Lebeau and Jean-Luc Blin}, doi = {10.1016/j.micromeso.2020.110376}, year = {2020}, date = {2020-10-01}, journal = {Microporous and Mesoporous Materials}, volume = {305}, pages = {110376}, abstract = {Concentrated emulsions have been widely considered as templates for the preparation of macroporous structures. Replacing concentrated emulsions by fine ones should rather lead to materials having large mesopores. However, fine emulsions were barely investigated for this purpose. On the other hand, mesostructured silica SBA-15 can be prepared from Pluronic P123 micelles according to the cooperative templating mechanism. Starting from mixture of fine emulsion and Pluronic P123 micelles, it is expected to obtain silicas with a controlled hierarchical mesoporosity. The fine emulsion has been formulated from the Kolliphor/Myristate/Water system. To get informations concerning the degree of compatibility between the two surfactants, which can affect the formation of the porous materials, the Kolliphor/P123/water system has been investigated in detail. The structural parameters of the mixed liquid crystal phases have been determined and the mixed micellar structure has been investigated by SAXS. The hierarchical porous silicas have been synthetized combining fine emulsion and Pluronic micellar solution. The materials porosity features strongly depend on the weight proportion between the fine emulsion and the P123 micelles. If this proportion is lower than 5/5, mesoporous silicas present a dual mesoporosity. By contrast, by increasing this proportion the mesopore size distribution only shows large mesopores.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Concentrated emulsions have been widely considered as templates for the preparation of macroporous structures. Replacing concentrated emulsions by fine ones should rather lead to materials having large mesopores. However, fine emulsions were barely investigated for this purpose. On the other hand, mesostructured silica SBA-15 can be prepared from Pluronic P123 micelles according to the cooperative templating mechanism. Starting from mixture of fine emulsion and Pluronic P123 micelles, it is expected to obtain silicas with a controlled hierarchical mesoporosity. The fine emulsion has been formulated from the Kolliphor/Myristate/Water system. To get informations concerning the degree of compatibility between the two surfactants, which can affect the formation of the porous materials, the Kolliphor/P123/water system has been investigated in detail. The structural parameters of the mixed liquid crystal phases have been determined and the mixed micellar structure has been investigated by SAXS. The hierarchical porous silicas have been synthetized combining fine emulsion and Pluronic micellar solution. The materials porosity features strongly depend on the weight proportion between the fine emulsion and the P123 micelles. If this proportion is lower than 5/5, mesoporous silicas present a dual mesoporosity. By contrast, by increasing this proportion the mesopore size distribution only shows large mesopores. |
Xu, Yangyang; Noirbent, Guillaume; Brunel, Damien; Ding, Zhaofu; Gigmes, Didier; Graff, Bernadette; Xiao, Pu; Dumur, Frederic; Lalevee, Jacques Novel ketone derivative-based photoinitiating systems for free radical polymerization under mild conditions and 3D printing (Article de journal) Polymer Chemistry, 11 (36), p. 5767–5777, 2020. @article{Xu2020bb, title = {Novel ketone derivative-based photoinitiating systems for free radical polymerization under mild conditions and 3D printing}, author = { Yangyang Xu and Guillaume Noirbent and Damien Brunel and Zhaofu Ding and Didier Gigmes and Bernadette Graff and Pu Xiao and Frederic Dumur and Jacques Lalevee}, doi = {10.1039/d0py00990c}, year = {2020}, date = {2020-09-01}, journal = {Polymer Chemistry}, volume = {11}, number = {36}, pages = {5767--5777}, abstract = {Photopolymerization of acrylates under mild conditions is promising not only for academic research but also for industrial applications. However, it still remains a huge challenge to develop effective photoinitiators or photoinitiating systems for the free radical polymerization of acrylates under visible light-emitting diode (LED) irradiation. In this work, twelve novel ketone derivatives containing either tertiary amines or anthracenes as peripheral substituting groups (noted as Ami-1-Ami-6 and Anth-1-Anth-6) were elaborately synthesized and proposed for the polymerization of di(trimethylolpropane) tetraacrylate (TA), a tetrafunctional polyether acrylate, under both thin and thick film conditions under LED@405 nm irradiation. Remarkably, eight of the selected ketones (Ami-2, Ami-6, Anth-1-Anth-6) had never been synthesized before. In combination with an amine and/or an iodonium salt (Iod), these ketones could form distinct photoinitiating systems, among which the Ami-2/amine/Iod system could lead to the highest final conversion of acrylates under the thick film (similar to 1.4 mm) conditions while the Ami-6/amine/Iod system could induce the highest final conversion of acrylates under the thin film (similar to 25 mu m) conditions. The photosensitivity of Ami-2 and Ami-6 was systematically investigated by steady state photolysis and fluorescence quenching experiments. Finally, the photocuring 3D printing technique was applied to TA, and both Ami-2- and Ami-6-based photoinitiating systems could be used to fabricate macroscopic 3D patterns with excellent spatial resolution.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Photopolymerization of acrylates under mild conditions is promising not only for academic research but also for industrial applications. However, it still remains a huge challenge to develop effective photoinitiators or photoinitiating systems for the free radical polymerization of acrylates under visible light-emitting diode (LED) irradiation. In this work, twelve novel ketone derivatives containing either tertiary amines or anthracenes as peripheral substituting groups (noted as Ami-1-Ami-6 and Anth-1-Anth-6) were elaborately synthesized and proposed for the polymerization of di(trimethylolpropane) tetraacrylate (TA), a tetrafunctional polyether acrylate, under both thin and thick film conditions under LED@405 nm irradiation. Remarkably, eight of the selected ketones (Ami-2, Ami-6, Anth-1-Anth-6) had never been synthesized before. In combination with an amine and/or an iodonium salt (Iod), these ketones could form distinct photoinitiating systems, among which the Ami-2/amine/Iod system could lead to the highest final conversion of acrylates under the thick film (similar to 1.4 mm) conditions while the Ami-6/amine/Iod system could induce the highest final conversion of acrylates under the thin film (similar to 25 mu m) conditions. The photosensitivity of Ami-2 and Ami-6 was systematically investigated by steady state photolysis and fluorescence quenching experiments. Finally, the photocuring 3D printing technique was applied to TA, and both Ami-2- and Ami-6-based photoinitiating systems could be used to fabricate macroscopic 3D patterns with excellent spatial resolution. |
Bataev, I A; Lazurenko, D V; Bataev, A A; Burov, V G; Ivanov, I V; Emurlaev, K I; Smirnov, A I; Rosenthal, M; Burghammer, M; Ivanov, D A; Georgarakis, K; Ruktuev, A A; Ogneva, T S; Jorge, A M J A novel operando approach to analyze the structural evolution of metallic materials during friction with application of synchrotron radiation (Article de journal) Acta Materialia, 196 , p. 355–369, 2020. @article{Bataev2020, title = {A novel operando approach to analyze the structural evolution of metallic materials during friction with application of synchrotron radiation}, author = { I. A. Bataev and D. V. Lazurenko and A. A. Bataev and V. G. Burov and I. V. Ivanov and K. I. Emurlaev and A. I. Smirnov and M. Rosenthal and M. Burghammer and D. A. Ivanov and K. Georgarakis and A. A. Ruktuev and T. S. Ogneva and A. M. J. Jorge}, doi = {10.1016/j.actamat.2020.06.049}, year = {2020}, date = {2020-09-01}, journal = {Acta Materialia}, volume = {196}, pages = {355--369}, abstract = {In this study, we describe an experimental setup and a new approach for operando investigation of structural evolution of materials during wear and friction. The setup is particularly suited for testing various friction pairs, including those in which both rubbing bodies are made of metals. The developed device allows circumventing the problems related to significant scattering of X-rays produced by metals and makes it possible using "real samples" in synchrotron beamlines operating in reflection mode. To demonstrate the capabilities of the device and the proposed new approach, an iron-based massive sample was subjected to thousands of friction cycles using a cemented carbide pin. The material was probed with synchrotron X-ray radiation within a few milliseconds after leaving the friction zone. The results of the microstructural and structural analysis, as well as results obtained from diverse mathematical models, allowed us to evaluate several features, including gradual accumulation of defects, microstructural refinement, dislocation density changes, surface layer oxidation, as well as several other phenomena caused by the dry sliding friction process. Mainly, it was possible to conclude that the process of wear occurred due to the cooperative action of oxidation and plastic deformation, which began during the first cycle of frictional interaction and was manifested in increasing the dislocation density, whose type was changed gradually during testing. The number of defects quickly reached a threshold value and subsequently fluctuated around it due to periodically repeated processes of defect accumulation and stress relaxation resulting from material wear. It was also observed that friction led to the quick formation of a mechanically mixed layer, consisting of the sample material and a mixture of two types of iron oxide - hematite and magnetite. The delamination of this layer was probably the primary wear mechanism. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this study, we describe an experimental setup and a new approach for operando investigation of structural evolution of materials during wear and friction. The setup is particularly suited for testing various friction pairs, including those in which both rubbing bodies are made of metals. The developed device allows circumventing the problems related to significant scattering of X-rays produced by metals and makes it possible using "real samples" in synchrotron beamlines operating in reflection mode. To demonstrate the capabilities of the device and the proposed new approach, an iron-based massive sample was subjected to thousands of friction cycles using a cemented carbide pin. The material was probed with synchrotron X-ray radiation within a few milliseconds after leaving the friction zone. The results of the microstructural and structural analysis, as well as results obtained from diverse mathematical models, allowed us to evaluate several features, including gradual accumulation of defects, microstructural refinement, dislocation density changes, surface layer oxidation, as well as several other phenomena caused by the dry sliding friction process. Mainly, it was possible to conclude that the process of wear occurred due to the cooperative action of oxidation and plastic deformation, which began during the first cycle of frictional interaction and was manifested in increasing the dislocation density, whose type was changed gradually during testing. The number of defects quickly reached a threshold value and subsequently fluctuated around it due to periodically repeated processes of defect accumulation and stress relaxation resulting from material wear. It was also observed that friction led to the quick formation of a mechanically mixed layer, consisting of the sample material and a mixture of two types of iron oxide - hematite and magnetite. The delamination of this layer was probably the primary wear mechanism. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. |
Ouachtak, Hassan; Akhouairi, Siham; Haounati, Redouane; Addi, Abdelaziz Ait; Jada, Amane; Taha, Mohamed Labd; Douch, Jamaa 3,4-Dihydroxybenzoic acid removal from water by goethite modified natural sand column fixed-bed: experimental study and mathematical modeling (Article de journal) Desalination and Water Treatment, 194 , p. 439–449, 2020. @article{Ouachtak2020, title = {3,4-Dihydroxybenzoic acid removal from water by goethite modified natural sand column fixed-bed: experimental study and mathematical modeling}, author = { Hassan Ouachtak and Siham Akhouairi and Redouane Haounati and Abdelaziz Ait Addi and Amane Jada and Mohamed Labd Taha and Jamaa Douch}, doi = {10.5004/dwt.2020.25562}, year = {2020}, date = {2020-08-01}, journal = {Desalination and Water Treatment}, volume = {194}, pages = {439--449}, abstract = {In this paper, a continuous adsorption of 3,4-Dihydroxybenzoic acid (3,4-DHBA) has been studied by using goethite modified natural sand (GMNS) as adsorbent in a fixed-bed column. Scanning electron microscopy coupled with energy-dispersive X-ray analysis, X-ray diffraction and Fourier transform infrared spectroscopy (FTIR), characterized the GMNS surface. The effect of various experimental parameters including pH (5 and 9), flow rate (1, 2, and 3 mL/min) and initial 3,4-DHBA concentration (15, 40 and 60 mg/L) on the transport and adsorption of 3,4-DHBA onto the column were investigated in detail. The obtained result shows that exhaustion time decreased with increasing initial 3,4-DHBA concentration, flow rate and pH. The highest value of adsorbed amount q = 35.66 mg/Kg was obtained from injection of 60 mg/L of initial 3,4-DHBA concentration solution with flow rate}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, a continuous adsorption of 3,4-Dihydroxybenzoic acid (3,4-DHBA) has been studied by using goethite modified natural sand (GMNS) as adsorbent in a fixed-bed column. Scanning electron microscopy coupled with energy-dispersive X-ray analysis, X-ray diffraction and Fourier transform infrared spectroscopy (FTIR), characterized the GMNS surface. The effect of various experimental parameters including pH (5 and 9), flow rate (1, 2, and 3 mL/min) and initial 3,4-DHBA concentration (15, 40 and 60 mg/L) on the transport and adsorption of 3,4-DHBA onto the column were investigated in detail. The obtained result shows that exhaustion time decreased with increasing initial 3,4-DHBA concentration, flow rate and pH. The highest value of adsorbed amount q = 35.66 mg/Kg was obtained from injection of 60 mg/L of initial 3,4-DHBA concentration solution with flow rate |
Marks, Evan A N; Kinigopoulou, Vasiliki; Akrout, Hanene; Azzaz, Ahmed Amine; Doulgeris, Charalampos; Jellali, Salah; Rad, Carlos; Zulueta, Paula Sanchez; Tziritis, Evangelos; El-Bassi, Leila; Ghimbeu, Camelia Matei; Jeguirim, Mejdi Potential for Production of Biochar-Based Fertilizers from Olive Mill Waste in Mediterranean Basin Countries: An Initial Assessment for Spain, Tunisia, and Greece (Article de journal) Sustainability, 12 (15), p. 6081, 2020. @article{Marks2020, title = {Potential for Production of Biochar-Based Fertilizers from Olive Mill Waste in Mediterranean Basin Countries: An Initial Assessment for Spain, Tunisia, and Greece}, author = { Evan A. N. Marks and Vasiliki Kinigopoulou and Hanene Akrout and Ahmed Amine Azzaz and Charalampos Doulgeris and Salah Jellali and Carlos Rad and Paula Sanchez Zulueta and Evangelos Tziritis and Leila El-Bassi and Camelia Matei Ghimbeu and Mejdi Jeguirim}, doi = {10.3390/su12156081}, year = {2020}, date = {2020-08-01}, journal = {Sustainability}, volume = {12}, number = {15}, pages = {6081}, abstract = {Olive mill wastes continue to be a management challenge due to the large volumes produced, particularly due to their toxicity and impacts on the environment. Thermal conversion through pyrolysis or hydrothermal carbonization techniques can detoxify wastes while conserving nutrient contents. In this work, we produced up-to-date data on olive mill waste flows in Spain, Tunisia, and Greece and characterized representative samples in the laboratory. Assays of thermal conversion of olive mill wastewaters and solid wastes were also performed to understand biochar yields and final properties, and the total quantities of nutrients contained were estimated. Of particular note were the quantities of potassium in Tunisian wastewaters, representing 0.6% of the total mass and an annual flow of approximately 5000 t, and in the Spanish solid wastes, an average of 1.7% of the total mass is potassium, representing an annual flow of approximately 23,000 t. Concerning phosphorus, Spanish solid wastes had the highest contents (0.1%), double that of other countries' wastes. Annually, olive mill wastes from the three countries are estimated to contain approximately 35 x 10(3)tons of potassium and 2.6 x 10(3)tons of phosphorus. With this resource converted to biochar, each year more than 700 km(2)of soils could be enriched in 0.2% carbon with biochar at an application rate of 7 t ha(-1).}, keywords = {}, pubstate = {published}, tppubtype = {article} } Olive mill wastes continue to be a management challenge due to the large volumes produced, particularly due to their toxicity and impacts on the environment. Thermal conversion through pyrolysis or hydrothermal carbonization techniques can detoxify wastes while conserving nutrient contents. In this work, we produced up-to-date data on olive mill waste flows in Spain, Tunisia, and Greece and characterized representative samples in the laboratory. Assays of thermal conversion of olive mill wastewaters and solid wastes were also performed to understand biochar yields and final properties, and the total quantities of nutrients contained were estimated. Of particular note were the quantities of potassium in Tunisian wastewaters, representing 0.6% of the total mass and an annual flow of approximately 5000 t, and in the Spanish solid wastes, an average of 1.7% of the total mass is potassium, representing an annual flow of approximately 23,000 t. Concerning phosphorus, Spanish solid wastes had the highest contents (0.1%), double that of other countries' wastes. Annually, olive mill wastes from the three countries are estimated to contain approximately 35 x 10(3)tons of potassium and 2.6 x 10(3)tons of phosphorus. With this resource converted to biochar, each year more than 700 km(2)of soils could be enriched in 0.2% carbon with biochar at an application rate of 7 t ha(-1). |
Anokhin, D V; Grafskaia, K N; Ivanov, D A; Ivan'kova, E M; Marikhin, V A; Myasnikova, L P; Ivanchev, S S Pattern of Monoclinic Phase Distribution in Nascent UHMWPE Particles (Article de journal) Physics of the Solid State, 62 (8), p. 1493–1499, 2020. @article{Anokhin2020, title = {Pattern of Monoclinic Phase Distribution in Nascent UHMWPE Particles}, author = { D. V Anokhin and K. N. Grafskaia and D. A. Ivanov and E. M. Ivan'kova and V. A. Marikhin and L. P. Myasnikova and S. S. Ivanchev}, doi = {10.1134/S1063783420080028}, year = {2020}, date = {2020-08-01}, journal = {Physics of the Solid State}, volume = {62}, number = {8}, pages = {1493--1499}, abstract = {By using the ID13 nanofocus beamline of the European Synchrotron Radiation Facility (Grenoble, France), an X-ray diffraction study of a "virgin" particle of ultra-high molecular weight polyethylene (UHMWPE) taken directly from the powder synthesis products and not subjected to any external mechanical action was carried out. The X-ray diffraction curves obtained by scanning a randomly selected region of the particle 100 x 20 mu m in size with a 0.3 x 0.3 mu m microbeam with a horizontal step of 2 mu m and vertical step of 0.5 mu m exhibited reflexes from the metastable monoclinic phase along with reflections from the orthorhombic phase. It can be supposed that it could be caused by the stresses that developed at specific structure formation during slurry synthesis and were preserved at cooling to room temperature and solvent evaporation. The possibility of the monoclinic phase localization in various morphological formations is discussed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } By using the ID13 nanofocus beamline of the European Synchrotron Radiation Facility (Grenoble, France), an X-ray diffraction study of a "virgin" particle of ultra-high molecular weight polyethylene (UHMWPE) taken directly from the powder synthesis products and not subjected to any external mechanical action was carried out. The X-ray diffraction curves obtained by scanning a randomly selected region of the particle 100 x 20 mu m in size with a 0.3 x 0.3 mu m microbeam with a horizontal step of 2 mu m and vertical step of 0.5 mu m exhibited reflexes from the metastable monoclinic phase along with reflections from the orthorhombic phase. It can be supposed that it could be caused by the stresses that developed at specific structure formation during slurry synthesis and were preserved at cooling to room temperature and solvent evaporation. The possibility of the monoclinic phase localization in various morphological formations is discussed. |
Chor, Ana; Goncalves, Raquel Pires; Costa, Andrea Machado; Farina, Marcos; Ponche, Arnaud; Sirelli, Lys; Schrodj, Gautier; Gree, Simon; de Andrade, Leonardo Rodrigues; Anselme, Karine; Dias, Marcos Lopes In Vitro Degradation of Electrospun Poly(Lactic-Co-Glycolic Acid) (PLGA) for Oral Mucosa Regeneration. (Article de journal) Polymers, 12 (8), 2020. @article{Chor2020, title = {In Vitro Degradation of Electrospun Poly(Lactic-Co-Glycolic Acid) (PLGA) for Oral Mucosa Regeneration.}, author = { Ana Chor and Raquel Pires Goncalves and Andrea Machado Costa and Marcos Farina and Arnaud Ponche and Lys Sirelli and Gautier Schrodj and Simon Gree and Leonardo Rodrigues de Andrade and Karine Anselme and Marcos Lopes Dias}, doi = {10.3390/polym12081853}, year = {2020}, date = {2020-08-01}, journal = {Polymers}, volume = {12}, number = {8}, abstract = {Poly(lactic-co-glycolic acid) (PLGA) has been used in the field of tissue engineering as a scaffold due to its good biocompatibility, biodegradability and mechanical strength. With the aim to explore the degradability of PLGA electrospun nonwoven structures for oral mucosa tissue engineering applications, non-irradiated and gamma irradiated nonwovens were immersed in three different solutions, in which simulated body fluid (SBF) and artificial saliva are important for future oral mucosa tissue engineering. The nonwovens were immersed for 7, 15 and 30 days in SBF, culture media (DMEM) and artificial saliva at 37 °C. Before immersion in the solutions, the dosage of 15 kGy was applied for sterilization in one assay and compared with non-irradiated samples at the same timepoints. Samples were characterized using different techniques such as scanning electron microscopy (SEM), differential scanning calorimetric (DSC) and gel permeation chromatography (GPC) to evaluate the nonwoven degradation and Fourier-transform infrared spectroscopy (FTIR) to evaluate the chain scissions. Our results showed that PLGA nonwovens were constituted by semicrystalline fibers with moderate degradation properties up to thirty days. The non-irradiated samples exhibited slower kinetics of degradation than irradiated nonwovens. For immersion times longer than 7 days in the three different solutions, the mean diameter of irradiated fibers stayed in the same range, but significantly different from the control sample. On non-irradiated samples, the degradation kinetics was slower and the plateau in the diameter value was only attained after 30 days of immersion in the fluids. Plasticization (fluid absorption into the fiber structure) occurred in the bulk material, as confirmed by a decrease in Tg observed by DSC analyses of non-irradiated and irradiated nonwovens, in comparison with the respective controls. In addition, artificial saliva showed a higher capacity of influencing PLGA crystallization than SBF and DMEM. FTIR analyses showed typical PLGA chemical functional groups changes. These results will be important for future application of those PLGA electrospun nonwovens for oral mucosa regeneration.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Poly(lactic-co-glycolic acid) (PLGA) has been used in the field of tissue engineering as a scaffold due to its good biocompatibility, biodegradability and mechanical strength. With the aim to explore the degradability of PLGA electrospun nonwoven structures for oral mucosa tissue engineering applications, non-irradiated and gamma irradiated nonwovens were immersed in three different solutions, in which simulated body fluid (SBF) and artificial saliva are important for future oral mucosa tissue engineering. The nonwovens were immersed for 7, 15 and 30 days in SBF, culture media (DMEM) and artificial saliva at 37 °C. Before immersion in the solutions, the dosage of 15 kGy was applied for sterilization in one assay and compared with non-irradiated samples at the same timepoints. Samples were characterized using different techniques such as scanning electron microscopy (SEM), differential scanning calorimetric (DSC) and gel permeation chromatography (GPC) to evaluate the nonwoven degradation and Fourier-transform infrared spectroscopy (FTIR) to evaluate the chain scissions. Our results showed that PLGA nonwovens were constituted by semicrystalline fibers with moderate degradation properties up to thirty days. The non-irradiated samples exhibited slower kinetics of degradation than irradiated nonwovens. For immersion times longer than 7 days in the three different solutions, the mean diameter of irradiated fibers stayed in the same range, but significantly different from the control sample. On non-irradiated samples, the degradation kinetics was slower and the plateau in the diameter value was only attained after 30 days of immersion in the fluids. Plasticization (fluid absorption into the fiber structure) occurred in the bulk material, as confirmed by a decrease in Tg observed by DSC analyses of non-irradiated and irradiated nonwovens, in comparison with the respective controls. In addition, artificial saliva showed a higher capacity of influencing PLGA crystallization than SBF and DMEM. FTIR analyses showed typical PLGA chemical functional groups changes. These results will be important for future application of those PLGA electrospun nonwovens for oral mucosa regeneration. |
Haddad, Khouloud; Jeguirim, Mejdi; Jellali, Salah; Thevenin, Nicolas; Ruidavets, Lionel; Limousy, Lionel Biochar production from Cypress sawdust and olive mill wastewater: Agronomic approach. (Article de journal) The Science of the total environment, 752 , p. 141713–141713, 2020. @article{Haddad2020, title = {Biochar production from Cypress sawdust and olive mill wastewater: Agronomic approach.}, author = { Khouloud Haddad and Mejdi Jeguirim and Salah Jellali and Nicolas Thevenin and Lionel Ruidavets and Lionel Limousy}, doi = {10.1016/j.scitotenv.2020.141713}, year = {2020}, date = {2020-08-01}, journal = {The Science of the total environment}, volume = {752}, pages = {141713--141713}, abstract = {Olive mill wastewater (OMW) is nowadays considered as a serious source pollution. At the same time, it contains high amounts of nutrients, especially potassium and phosphorus that could be recovered for agricultural purposes. The aim of the current experimental research work is to investigate the agronomic potential use of OMW based biochar produced from the slow pyrolysis at 500°C of raw cypress sawdust (CS) impregnated with OMW (ICS-OMW-B). In order to understand the contribution of OMW, two additional biochars were produced from raw cypress sawdust (RCS-B) and cypress sawdust pretreated with potassium chloride (ICS-K-B). Results indicated that RCS impregnation by OMW significantly improved the produced biochar's chemical properties, especially its nutrients contents. Furthermore, in comparison with the other biochars, ICS-OMW-B application as an organic fertilizer showed promising results in terms of produced fresh and dry masses, as well as potassium bioavailability as assessed in test experiments with ryegrass. For instance, the dry matter masses of the rye-grass treated with ICS-OMW-B were about 23, 34 and 50wt% higher than the ones measured for the tests using RCS-B, ICS-K-B and synthetic K-fertilizer as amendments, respectively. Besides, this biochar has a potential effect on the suppression of various pathogens existing in the tested agricultural soil. All these results demonstrated that the biochar generated from the slow pyrolysis of impregnated sawdust with OMW could be considered as attractive and promising organic fertilizer for acidic agricultural soils.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Olive mill wastewater (OMW) is nowadays considered as a serious source pollution. At the same time, it contains high amounts of nutrients, especially potassium and phosphorus that could be recovered for agricultural purposes. The aim of the current experimental research work is to investigate the agronomic potential use of OMW based biochar produced from the slow pyrolysis at 500°C of raw cypress sawdust (CS) impregnated with OMW (ICS-OMW-B). In order to understand the contribution of OMW, two additional biochars were produced from raw cypress sawdust (RCS-B) and cypress sawdust pretreated with potassium chloride (ICS-K-B). Results indicated that RCS impregnation by OMW significantly improved the produced biochar's chemical properties, especially its nutrients contents. Furthermore, in comparison with the other biochars, ICS-OMW-B application as an organic fertilizer showed promising results in terms of produced fresh and dry masses, as well as potassium bioavailability as assessed in test experiments with ryegrass. For instance, the dry matter masses of the rye-grass treated with ICS-OMW-B were about 23, 34 and 50wt% higher than the ones measured for the tests using RCS-B, ICS-K-B and synthetic K-fertilizer as amendments, respectively. Besides, this biochar has a potential effect on the suppression of various pathogens existing in the tested agricultural soil. All these results demonstrated that the biochar generated from the slow pyrolysis of impregnated sawdust with OMW could be considered as attractive and promising organic fertilizer for acidic agricultural soils. |
Garra, Patxi; Fouassier, Jean Pierre; Lakhdar, Sami; Yagci, Yusuf; Lalevee, Jacques Visible light photoinitiating systems by charge transfer complexes: Photochemistry without dyes (Article de journal) Progress in Polymer Science, 107 , p. 101277, 2020. @article{Garra2020, title = {Visible light photoinitiating systems by charge transfer complexes: Photochemistry without dyes}, author = { Patxi Garra and Jean Pierre Fouassier and Sami Lakhdar and Yusuf Yagci and Jacques Lalevee}, doi = {10.1016/j.progpolymsci.2020.101277}, year = {2020}, date = {2020-08-01}, journal = {Progress in Polymer Science}, volume = {107}, pages = {101277}, abstract = {Visible light induced synthesis generally involves i) dyes or chromophores with potential photocleavable bonds (Type I photoinitiator), ii) hydrogen abstractions (Type II photoinitiator) by dyes/chromphores and iii) photoredox catalysis using metal-based or metal-free dyes. Beyond these strategies, charge transfer complexes (CTCs), also referred to as electron donor acceptor (EDA) complexes, were also reported to be the visible light initiating species. In these cases, the ground state intimate association of a donor and acceptor creates a new structure that can result in (bathochromic) visible light absorption compared to the separated compounds. In the present review, an update on CTCs as photoinitiating systems for photopoly-merization applications will be provided with examples of CTC-specific structure/reactivity/efficiency relationships. Interestingly, CTC can act as dual photo/thermal photoinitiators both in cationic and free radical photopolymerizations. Also, low optical density of the CTC in resins allowed to access extremely thick samples and composites. The possibility of extending wavelength sensitivity of photopolymerizations by excited state complexes (exciplexes) is also discussed. (C) 2020 Elsevier B.V. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Visible light induced synthesis generally involves i) dyes or chromophores with potential photocleavable bonds (Type I photoinitiator), ii) hydrogen abstractions (Type II photoinitiator) by dyes/chromphores and iii) photoredox catalysis using metal-based or metal-free dyes. Beyond these strategies, charge transfer complexes (CTCs), also referred to as electron donor acceptor (EDA) complexes, were also reported to be the visible light initiating species. In these cases, the ground state intimate association of a donor and acceptor creates a new structure that can result in (bathochromic) visible light absorption compared to the separated compounds. In the present review, an update on CTCs as photoinitiating systems for photopoly-merization applications will be provided with examples of CTC-specific structure/reactivity/efficiency relationships. Interestingly, CTC can act as dual photo/thermal photoinitiators both in cationic and free radical photopolymerizations. Also, low optical density of the CTC in resins allowed to access extremely thick samples and composites. The possibility of extending wavelength sensitivity of photopolymerizations by excited state complexes (exciplexes) is also discussed. (C) 2020 Elsevier B.V. All rights reserved. |
Narayanan, Lakshmi Kanthan; Sankaranarayanan, Suresh; Rodrigues, Joel J P C; Lorenz, Pascal Multi-Agent-Based Modeling for Underground Pipe Health and Water Quality Monitoring for Supplying Quality Water (Article de journal) International Journal of Intelligent Information Technologies, 16 (3), p. 52–79, 2020. @article{Narayanan2020, title = {Multi-Agent-Based Modeling for Underground Pipe Health and Water Quality Monitoring for Supplying Quality Water}, author = { Lakshmi Kanthan Narayanan and Suresh Sankaranarayanan and Joel J. P. C. Rodrigues and Pascal Lorenz}, doi = {10.4018/IJIIT.2020070103}, year = {2020}, date = {2020-07-01}, journal = {International Journal of Intelligent Information Technologies}, volume = {16}, number = {3}, pages = {52--79}, abstract = {This article discusses distributed monitoring through the deployment of various multiagents in the IoT-Fog-based water distribution network (WDN). This will ensure the right amount of water supplied with respect to demand forecasted to residents. In addition, underground pipe health is also monitored by means of a multiagent based on hydraulic parameters supplying water forecasted with minimal losses which would minimize the operational and material cost involved in recovery or repair. Lastly, there are agents deployed towards leakage monitoring and anti-theft detection of water. The multiagents act upon various parameters of hydrology and analysis is based on the data acquired by the various sensors deployed in the water distribution network which perform partial automation of the disconnection of the supply during extreme critical conditions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This article discusses distributed monitoring through the deployment of various multiagents in the IoT-Fog-based water distribution network (WDN). This will ensure the right amount of water supplied with respect to demand forecasted to residents. In addition, underground pipe health is also monitored by means of a multiagent based on hydraulic parameters supplying water forecasted with minimal losses which would minimize the operational and material cost involved in recovery or repair. Lastly, there are agents deployed towards leakage monitoring and anti-theft detection of water. The multiagents act upon various parameters of hydrology and analysis is based on the data acquired by the various sensors deployed in the water distribution network which perform partial automation of the disconnection of the supply during extreme critical conditions. |
del Rios, Carolina Mar Saavedra; Simonin, Loic; de Geyer, Arnaud; Ghimbeu, Camelia Matei; Dupont, Capucine Unraveling the Properties of Biomass-Derived Hard Carbons upon Thermal Treatment for a Practical Application in Na-Ion Batteries (Article de journal) Energies, 13 (14), p. 3513, 2020. @article{Rios2020, title = {Unraveling the Properties of Biomass-Derived Hard Carbons upon Thermal Treatment for a Practical Application in Na-Ion Batteries}, author = { Carolina del Mar Saavedra Rios and Loic Simonin and Arnaud de Geyer and Camelia Matei Ghimbeu and Capucine Dupont}, doi = {10.3390/en13143513}, year = {2020}, date = {2020-07-01}, journal = {Energies}, volume = {13}, number = {14}, pages = {3513}, abstract = {Biomass is gaining increased attention as a sustainable and low-cost hard carbon (HC) precursor. However, biomass properties are often unexplored and unrelated to HC performance. Herein, we used pine, beechwood, miscanthus, and wheat straw precursors to synthesize HCs at 1000 degrees C, 1200 degrees C and 1400 degrees C by a two-steps pyrolysis treatment. The final physicochemical and electrochemical properties of the HC evidenced dissimilar trends, mainly influenced by the precursor's inorganic content, and less by the thermal treatment. Pine and beechwood HCs delivered the highest reversible capacity and coulombic efficiency (CE) at 1400 degrees C of about 300 mAh center dot g(-1)and 80%, respectively. This performance can be attributed to the structure derived from the high carbon purity precursors. Miscanthus and wheat straw HC performance was strongly affected by the silicon, potassium, and calcium content in the biomasses, which promoted simultaneous detrimental phenomena of intrinsic activation, formation of a silicon carbide phase, and growth of graphitic domains with temperature. The latter HCs delivered 240-200 mAh center dot g(-1)of reversible capacity and 70-60% of CE, respectively, at 1400 degrees C. The biomass precursor composition, especially its inorganic fraction, seems to be a key parameter to control, for obtaining high performance hard carbon electrodes by direct pyrolysis process.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Biomass is gaining increased attention as a sustainable and low-cost hard carbon (HC) precursor. However, biomass properties are often unexplored and unrelated to HC performance. Herein, we used pine, beechwood, miscanthus, and wheat straw precursors to synthesize HCs at 1000 degrees C, 1200 degrees C and 1400 degrees C by a two-steps pyrolysis treatment. The final physicochemical and electrochemical properties of the HC evidenced dissimilar trends, mainly influenced by the precursor's inorganic content, and less by the thermal treatment. Pine and beechwood HCs delivered the highest reversible capacity and coulombic efficiency (CE) at 1400 degrees C of about 300 mAh center dot g(-1)and 80%, respectively. This performance can be attributed to the structure derived from the high carbon purity precursors. Miscanthus and wheat straw HC performance was strongly affected by the silicon, potassium, and calcium content in the biomasses, which promoted simultaneous detrimental phenomena of intrinsic activation, formation of a silicon carbide phase, and growth of graphitic domains with temperature. The latter HCs delivered 240-200 mAh center dot g(-1)of reversible capacity and 70-60% of CE, respectively, at 1400 degrees C. The biomass precursor composition, especially its inorganic fraction, seems to be a key parameter to control, for obtaining high performance hard carbon electrodes by direct pyrolysis process. |
Sprick, Elodie; Graff, Bernadette; Becht, Jean-Michel; Tigges, Thomas; Neuhaus, Kira; Weber, Christoph; Lalevee, Jacques New bio-sourced hydrogen donors as high performance coinitiators and additives for CQ-based systems: Toward aromatic amine-free photoinitiating systems (Article de journal) European Polymer Journal, 134 , p. 109794, 2020. @article{Sprick2020a, title = {New bio-sourced hydrogen donors as high performance coinitiators and additives for CQ-based systems: Toward aromatic amine-free photoinitiating systems}, author = { Elodie Sprick and Bernadette Graff and Jean-Michel Becht and Thomas Tigges and Kira Neuhaus and Christoph Weber and Jacques Lalevee}, doi = {10.1016/j.eurpolymj.2020.109794}, year = {2020}, date = {2020-07-01}, journal = {European Polymer Journal}, volume = {134}, pages = {109794}, abstract = {Two new hydrogen-donors synthesized from natural products (curcumin and 4-methylumbelliferone) are proposed here as new classes of high performance bio-sourced coinitiators (BHD) for the polymerization of methacrylates under blue light irradiation. In presence of these naturally derived compounds good polymerization performances are reached and good bleaching properties are obtained compared to traditionally used camphorquinone (CQ)-based systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two new hydrogen-donors synthesized from natural products (curcumin and 4-methylumbelliferone) are proposed here as new classes of high performance bio-sourced coinitiators (BHD) for the polymerization of methacrylates under blue light irradiation. In presence of these naturally derived compounds good polymerization performances are reached and good bleaching properties are obtained compared to traditionally used camphorquinone (CQ)-based systems. |
Abdallah, Mira; Hijazi, Akram; Graff, Bernadette; Fouassier, Jean-Pierre; Dumur, Frederic; Lalevee, Jacques In Silico Design of Nitrocoumarins as Near-UV Photoinitiators: Toward Interesting Opportunities in Composites and 3D Printing Technologies (Article de journal) Acs Applied Polymer Materials, 2 (7), p. 2890–2901, 2020. @article{Abdallah2020c, title = {In Silico Design of Nitrocoumarins as Near-UV Photoinitiators: Toward Interesting Opportunities in Composites and 3D Printing Technologies}, author = { Mira Abdallah and Akram Hijazi and Bernadette Graff and Jean-Pierre Fouassier and Frederic Dumur and Jacques Lalevee}, doi = {10.1021/acsapm.0c00409}, year = {2020}, date = {2020-07-01}, journal = {Acs Applied Polymer Materials}, volume = {2}, number = {7}, pages = {2890--2901}, abstract = {In this research, 31 nitrocoumarins (including 27 structures never reported in the literature) were designed through molecular orbital calculations and synthesized as high-performance near-UV-visible light photoinitiators of polymerization for a better understanding of their structure/reactivity/efficiency relationship. Based on their photoinitiating abilities examined during the free-radical polymerization (FRP) of acrylates, different coumarins examined in this work can be classified into three main categories: (1) very reactive ones (Coum6,7,11,12 & 26); (2) moderately reactive nitrocoumarins (Coum1,2,16,20,21,23,25,27 & 28); and (3) nitrocoumarins of low reactivity (Coum3,4,5,8,9,10,13,14,15,17,18,19,22,24,29,30&31). Different techniques were used in order to understand their photoinitiating abilities as well as the associated chemical mechanisms. The real-time Fourier transform infrared technique has been used to follow the polymerization profiles (reactive function conversion (FCs) vs irradiation time). Different two- and three-component photoinitiating systems based on nitrocoumarin/iodonium salt (or N-phenylglycine (NPG) or ethyl 4-(dimethylamino)benzoate) and nitrocoumarin/iodonium salt/NPG were examined for the FRP of acrylates or/and the cationic polymerization of epoxides upon irradiation with a light-emitting diode at 405 nm as an unharmed and inexpensive irradiation source. Moreover, cyclic voltammetry, fluorescence spectroscopy, UV-visible spectroscopy, and electron spin resonance techniques were also used to provide a full picture of the involved chemical mechanisms. Excellent polymerization performances (i.e., high final reactive FCs and also great rates of polymerization (R-p) were obtained using these derivatives. Some applications in three-dimensional printing and composite synthesis are reported to highlight the interest of the proposed structures in modern technologies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this research, 31 nitrocoumarins (including 27 structures never reported in the literature) were designed through molecular orbital calculations and synthesized as high-performance near-UV-visible light photoinitiators of polymerization for a better understanding of their structure/reactivity/efficiency relationship. Based on their photoinitiating abilities examined during the free-radical polymerization (FRP) of acrylates, different coumarins examined in this work can be classified into three main categories: (1) very reactive ones (Coum6,7,11,12 & 26); (2) moderately reactive nitrocoumarins (Coum1,2,16,20,21,23,25,27 & 28); and (3) nitrocoumarins of low reactivity (Coum3,4,5,8,9,10,13,14,15,17,18,19,22,24,29,30&31). Different techniques were used in order to understand their photoinitiating abilities as well as the associated chemical mechanisms. The real-time Fourier transform infrared technique has been used to follow the polymerization profiles (reactive function conversion (FCs) vs irradiation time). Different two- and three-component photoinitiating systems based on nitrocoumarin/iodonium salt (or N-phenylglycine (NPG) or ethyl 4-(dimethylamino)benzoate) and nitrocoumarin/iodonium salt/NPG were examined for the FRP of acrylates or/and the cationic polymerization of epoxides upon irradiation with a light-emitting diode at 405 nm as an unharmed and inexpensive irradiation source. Moreover, cyclic voltammetry, fluorescence spectroscopy, UV-visible spectroscopy, and electron spin resonance techniques were also used to provide a full picture of the involved chemical mechanisms. Excellent polymerization performances (i.e., high final reactive FCs and also great rates of polymerization (R-p) were obtained using these derivatives. Some applications in three-dimensional printing and composite synthesis are reported to highlight the interest of the proposed structures in modern technologies. |
Abdallah, Mira; Hijazi, Akram; Lin, Jui-Teng; Graff, Bernadette; Dumur, Frederic; Lalevee, Jacques Coumarin Derivatives as Photoinitiators in Photo-Oxidation and Photo-Reduction Processes and a Kinetic Model for Simulations of the Associated Polymerization Profiles (Article de journal) Acs Applied Polymer Materials, 2 (7), p. 2769–2780, 2020. @article{Abdallah2020b, title = {Coumarin Derivatives as Photoinitiators in Photo-Oxidation and Photo-Reduction Processes and a Kinetic Model for Simulations of the Associated Polymerization Profiles}, author = { Mira Abdallah and Akram Hijazi and Jui-Teng Lin and Bernadette Graff and Frederic Dumur and Jacques Lalevee}, doi = {10.1021/acsapm.0c00340}, year = {2020}, date = {2020-07-01}, journal = {Acs Applied Polymer Materials}, volume = {2}, number = {7}, pages = {2769--2780}, abstract = {In this work, the design of an original series of coumarin derivatives CoumC1-CoumC13) is presented. Chemical structures of these coumarins were selected by molecular modeling to ensure both excellent light absorption properties and high potential photoreactivity (high excited-state energy). As a striking result of this in silico design, eight of the 13 proposed coumarins were never presented and were specifically proposed for this work, indicating the interest in their structures. New multicomponent photoinitiating systems (PISs) based on these coumarins are proposed for the free radical polymerization (FRP) of (meth)acrylates and examined upon visible light irradiation using a light-emitting diode (LED) as a safe and economical irradiation source. The proposed systems are based on coumarins that act as remarkable photoinitiators/photosensitizers (PIs/PSs) combined with N-phenyl-glycine (NPG) and/or iodonium salt (Iod) as co-initiators to generate the reactive species (radicals) that will initiate the photopolymerization reaction. Investigations of the chemical mechanisms suggested by the different interactions that take place as well as the photophysical and photochemical properties of coumarins are provided. It is possible to obtain high polymerization rates (R-p), excellent photoinitiating abilities, and great reactive function conversions (FC) with these structures based on the coumarin core. Coumarins show high efficiency for the FRP of (meth)acrylates by reaction with iodonium salt (a photo-oxidation process) or with amine (a photo-reduction process). These compounds were used in three-dimensional (3D) printing resins but also for the preparation of photocomposites. In this latter case, excellent depth of cure was noted as remarkable behavior. To rationalize the experimental results, a kinetic model for a three-component system has been established to analyze the role of oxygen in the monomer conversions and the conversion enhancement observed while using an amine as a co-initiator.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this work, the design of an original series of coumarin derivatives CoumC1-CoumC13) is presented. Chemical structures of these coumarins were selected by molecular modeling to ensure both excellent light absorption properties and high potential photoreactivity (high excited-state energy). As a striking result of this in silico design, eight of the 13 proposed coumarins were never presented and were specifically proposed for this work, indicating the interest in their structures. New multicomponent photoinitiating systems (PISs) based on these coumarins are proposed for the free radical polymerization (FRP) of (meth)acrylates and examined upon visible light irradiation using a light-emitting diode (LED) as a safe and economical irradiation source. The proposed systems are based on coumarins that act as remarkable photoinitiators/photosensitizers (PIs/PSs) combined with N-phenyl-glycine (NPG) and/or iodonium salt (Iod) as co-initiators to generate the reactive species (radicals) that will initiate the photopolymerization reaction. Investigations of the chemical mechanisms suggested by the different interactions that take place as well as the photophysical and photochemical properties of coumarins are provided. It is possible to obtain high polymerization rates (R-p), excellent photoinitiating abilities, and great reactive function conversions (FC) with these structures based on the coumarin core. Coumarins show high efficiency for the FRP of (meth)acrylates by reaction with iodonium salt (a photo-oxidation process) or with amine (a photo-reduction process). These compounds were used in three-dimensional (3D) printing resins but also for the preparation of photocomposites. In this latter case, excellent depth of cure was noted as remarkable behavior. To rationalize the experimental results, a kinetic model for a three-component system has been established to analyze the role of oxygen in the monomer conversions and the conversion enhancement observed while using an amine as a co-initiator. |
Lebeau, Benedicte; Naboulsi, Issam; Michelin, Laure; Marichal, Claire; Rigolet, Severinne; Carteret, Cedric; Brunet, Sylvette; Bonne, Magali; Blin, Jean-Luc Amorphous mesostructured zirconia with high (hydro)thermal stability (Article de journal) Rsc Advances, 10 (44), p. 26165–26176, 2020. @article{Lebeau2020, title = {Amorphous mesostructured zirconia with high (hydro)thermal stability}, author = { Benedicte Lebeau and Issam Naboulsi and Laure Michelin and Claire Marichal and Severinne Rigolet and Cedric Carteret and Sylvette Brunet and Magali Bonne and Jean-Luc Blin}, doi = {10.1039/d0ra04824k}, year = {2020}, date = {2020-07-01}, journal = {Rsc Advances}, volume = {10}, number = {44}, pages = {26165--26176}, abstract = {Here, combining the evaporation-induced self-assembly (EISA) method and the liquid crystal templating pathway, mesostructured amorphous zirconium oxides have been prepared by a soft templating method without addition of any heteroelement to stabilize the mesopore framework. The recovered materials have been characterized by SAXS measurements, nitrogen adsorption-desorption analysis and X-ray diffraction (XRD). The obtained mesostructured zirconia exhibits a high thermal stability. Anin situXRD study performed as a function of temperature shows that the amorphous ZrO2, obtained after removal of the pore templating agent (pluronic P123), begins to crystallize in air from 420 degrees C. Amorphous mesostructured ZrO(2)also presents a high hydrothermal stability; these materials are not degraded after 72 hours in boiling water.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Here, combining the evaporation-induced self-assembly (EISA) method and the liquid crystal templating pathway, mesostructured amorphous zirconium oxides have been prepared by a soft templating method without addition of any heteroelement to stabilize the mesopore framework. The recovered materials have been characterized by SAXS measurements, nitrogen adsorption-desorption analysis and X-ray diffraction (XRD). The obtained mesostructured zirconia exhibits a high thermal stability. Anin situXRD study performed as a function of temperature shows that the amorphous ZrO2, obtained after removal of the pore templating agent (pluronic P123), begins to crystallize in air from 420 degrees C. Amorphous mesostructured ZrO(2)also presents a high hydrothermal stability; these materials are not degraded after 72 hours in boiling water. |
Litvinov, Victor; Deblieck, Rudy; Clair, Charles; den Fonteyne, Winke Van; Lallam, Abdelaziz; Kleppinger, Ralf; Ivanov, Dimitri A; Ries, Michael E; Boerakker, Mark Molecular Structure, Phase Composition, Melting Behavior, and Chain Entanglements in the Amorphous Phase of High-Density Polyethylenes (Article de journal) Macromolecules, 53 (13), p. 5418–5433, 2020. @article{Litvinov2020, title = {Molecular Structure, Phase Composition, Melting Behavior, and Chain Entanglements in the Amorphous Phase of High-Density Polyethylenes}, author = { Victor Litvinov and Rudy Deblieck and Charles Clair and Winke Van den Fonteyne and Abdelaziz Lallam and Ralf Kleppinger and Dimitri A. Ivanov and Michael E. Ries and Mark Boerakker}, doi = {10.1021/acs.macromol.0c00956}, year = {2020}, date = {2020-07-01}, journal = {Macromolecules}, volume = {53}, number = {13}, pages = {5418--5433}, abstract = {A methodology for estimating the entanglement density in the amorphous phase of semicrystalline polyolefins was developed. The method is based on the analysis of the density of physical network junctions in the amorphous phase by H-1 NMR T-2 relaxation experiments. The density of the entanglement network was estimated for melt- and high-pressure-crystallized high-density polyethylenes (HDPEs) at temperatures close to and gradually approaching melting. Its value is lower for high-pressure-crystallized HDPE than for the same melt-crystallized polymer. The network of entanglements is characterized by the fraction of entangled network chains, the weight-average molecular weight of the network chains between apparent chain entanglements, M-e, and the volume average density of apparent chain entanglements. The entanglement network was studied in a series of low- and high-molecular-weight HDPEs and bimodal HDPE samples with different molecular weight characteristics and densities controlled by different contents of the 1-butene comonomer. It turns out that the molecular weight characteristics of the HDPEs influence the entanglement network. The fraction of network chains and the average density of apparent chain entanglements decrease with decreasing molecular weight M-n due to the "dilution" effect caused by disentangled chain-end segments increasing the M-e. The current methodology is of interest for studying the effect of crystallization conditions, molecular structures, and short-chain branches on phase composition, melting behavior, and chain entanglements in the amorphous phase of polyolefins. The method allows estimation of the fraction of network chains, which potentially can form tie-chain segments during deformation. The effect of short-chain branches and molecular weight characteristics on the creep response of polyolefins is discussed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A methodology for estimating the entanglement density in the amorphous phase of semicrystalline polyolefins was developed. The method is based on the analysis of the density of physical network junctions in the amorphous phase by H-1 NMR T-2 relaxation experiments. The density of the entanglement network was estimated for melt- and high-pressure-crystallized high-density polyethylenes (HDPEs) at temperatures close to and gradually approaching melting. Its value is lower for high-pressure-crystallized HDPE than for the same melt-crystallized polymer. The network of entanglements is characterized by the fraction of entangled network chains, the weight-average molecular weight of the network chains between apparent chain entanglements, M-e, and the volume average density of apparent chain entanglements. The entanglement network was studied in a series of low- and high-molecular-weight HDPEs and bimodal HDPE samples with different molecular weight characteristics and densities controlled by different contents of the 1-butene comonomer. It turns out that the molecular weight characteristics of the HDPEs influence the entanglement network. The fraction of network chains and the average density of apparent chain entanglements decrease with decreasing molecular weight M-n due to the "dilution" effect caused by disentangled chain-end segments increasing the M-e. The current methodology is of interest for studying the effect of crystallization conditions, molecular structures, and short-chain branches on phase composition, melting behavior, and chain entanglements in the amorphous phase of polyolefins. The method allows estimation of the fraction of network chains, which potentially can form tie-chain segments during deformation. The effect of short-chain branches and molecular weight characteristics on the creep response of polyolefins is discussed. |
Diboune, Mathieu; Nouali, Habiba; Soulard, Michel; Patarin, Joel; Rioland, Guillaume; Faye, Delphine; Daou, Jean T Efficient Removal of Volatile Organic Compounds by FAU-Type Zeolite Coatings. (Article de journal) Molecules (Basel, Switzerland), 25 (15), 2020. @article{Diboune2020, title = {Efficient Removal of Volatile Organic Compounds by FAU-Type Zeolite Coatings.}, author = { Mathieu Diboune and Habiba Nouali and Michel Soulard and Joel Patarin and Guillaume Rioland and Delphine Faye and T. Jean Daou}, doi = {10.3390/molecules25153336}, year = {2020}, date = {2020-07-01}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {15}, abstract = {Silicone and pure organic binders were used to develop FAU-type zeolite coatings applied on pre-treated aluminum substrates by using a spraying method and then cured under specific conditions. The influence of the amount of binder on adhesion properties of zeolite coatings was first investigated to determine the optimum ratio between zeolite and binder. Zeolite coatings were then elaborated with a high zeolite content (between 70 and 80 wt.%) to ensure high adsorption capacities. The amount of binders involved in different zeolite coatings was sufficient to achieve interesting adhesion and cohesion properties. The accessibility of zeolite microporosity was studied by nitrogen adsorption-desorption measurements, which revealed a very small or no loss of the micropore volume for the optimized coatings. Volatile Organic Compounds (VOCs) adsorption measurements were carried out using n-hexane as probe molecule. FAU-type zeolite in powder form adsorbs 180 mg/ganhydrous zeolite, whereas the amounts of n-hexane adsorbed by zeolite coatings ranged from 131 to 175 mg/ganhydrous zeolite.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Silicone and pure organic binders were used to develop FAU-type zeolite coatings applied on pre-treated aluminum substrates by using a spraying method and then cured under specific conditions. The influence of the amount of binder on adhesion properties of zeolite coatings was first investigated to determine the optimum ratio between zeolite and binder. Zeolite coatings were then elaborated with a high zeolite content (between 70 and 80 wt.%) to ensure high adsorption capacities. The amount of binders involved in different zeolite coatings was sufficient to achieve interesting adhesion and cohesion properties. The accessibility of zeolite microporosity was studied by nitrogen adsorption-desorption measurements, which revealed a very small or no loss of the micropore volume for the optimized coatings. Volatile Organic Compounds (VOCs) adsorption measurements were carried out using n-hexane as probe molecule. FAU-type zeolite in powder form adsorbs 180 mg/ganhydrous zeolite, whereas the amounts of n-hexane adsorbed by zeolite coatings ranged from 131 to 175 mg/ganhydrous zeolite. |
Caillosse, Etienne; Zaier, Mohamed; Mezghani, Mariam; Hajjar-Garreau, Samar; Vidal, Loic; Lougnot, Daniel; Balan, Lavinia Photo-Induced Self-Assembly of Silver Nanoparticles for Rapid Generation of First and Second Surface Mirrors (Article de journal) Acs Applied Nano Materials, 3 (7), p. 6531–6540, 2020. @article{Caillosse2020, title = {Photo-Induced Self-Assembly of Silver Nanoparticles for Rapid Generation of First and Second Surface Mirrors}, author = { Etienne Caillosse and Mohamed Zaier and Mariam Mezghani and Samar Hajjar-Garreau and Loic Vidal and Daniel Lougnot and Lavinia Balan}, doi = {10.1021/acsanm.0c01010}, year = {2020}, date = {2020-07-01}, journal = {Acs Applied Nano Materials}, volume = {3}, number = {7}, pages = {6531--6540}, abstract = {Interesting mirror-like, highly reflective, and conductive silver films have been successfully generated directly on a glass slide using a simple and fast photoinduced approach. A water-based photosensitive formulation containing the silver precursor and a photogenerator of free radicals was used. It was applied like paint and exposed to UV light for a few seconds, in the absence of any additional reducing agents and without further treatment of any kind. This approach allowed ultrathin films of silver nanoparticles to be generated in situ (AgNPs) on the back side of the glass substrate. The particles are homogeneously autoassembled onto the glass surface and the glass/silver diopter exhibits a high reflective character. With such an experimental arrangement, reflective surfaces are obtained: in contact with the glass slide, which is called the second surface mirror, and on the air side, which is called the first surface mirror. Quite interestingly, these reflective and conductive thin films exhibit strong natural adhesion on the glass substrate without the need for enhancing treatments (sensitization or activation) to improve the adhesion of the silver layer to the glass, as usual with silver glass mirrors. The influence of several chemical and photonic parameters has been examined in order to optimize the final optical and electrical properties of these silver films.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Interesting mirror-like, highly reflective, and conductive silver films have been successfully generated directly on a glass slide using a simple and fast photoinduced approach. A water-based photosensitive formulation containing the silver precursor and a photogenerator of free radicals was used. It was applied like paint and exposed to UV light for a few seconds, in the absence of any additional reducing agents and without further treatment of any kind. This approach allowed ultrathin films of silver nanoparticles to be generated in situ (AgNPs) on the back side of the glass substrate. The particles are homogeneously autoassembled onto the glass surface and the glass/silver diopter exhibits a high reflective character. With such an experimental arrangement, reflective surfaces are obtained: in contact with the glass slide, which is called the second surface mirror, and on the air side, which is called the first surface mirror. Quite interestingly, these reflective and conductive thin films exhibit strong natural adhesion on the glass substrate without the need for enhancing treatments (sensitization or activation) to improve the adhesion of the silver layer to the glass, as usual with silver glass mirrors. The influence of several chemical and photonic parameters has been examined in order to optimize the final optical and electrical properties of these silver films. |
Tkachenko, Vitalii; Vidal, Loic; Josien, Ludovic; Schmutz, Marc; Poly, Julien; Chemtob, Abraham Characterizing the Core-Shell Architecture of Block Copolymer Nanoparticles with Electron Microscopy: A Multi-Technique Approach. (Article de journal) Polymers, 12 (8), 2020. @article{Tkachenko2020b, title = {Characterizing the Core-Shell Architecture of Block Copolymer Nanoparticles with Electron Microscopy: A Multi-Technique Approach.}, author = { Vitalii Tkachenko and Loic Vidal and Ludovic Josien and Marc Schmutz and Julien Poly and Abraham Chemtob}, doi = {10.3390/polym12081656}, year = {2020}, date = {2020-07-01}, journal = {Polymers}, volume = {12}, number = {8}, abstract = {Electron microscopy has proved to be a major tool to study the structure of self-assembled amphiphilic block copolymer particles. These specimens, like supramolecular biological structures, are problematic for electron microscopy because of their poor capacity to scatter electrons and their susceptibility to radiation damage and dehydration. Sub-50 nm core-shell spherical particles made up of poly(hydroxyethyl acrylate)-b-poly(styrene) are prepared via polymerization-induced self-assembly (PISA). For their morphological characterization, we discuss the advantages, limitations, and artefacts of TEM with or without staining, cryo-TEM, and SEM. A number of technical points are addressed such as precisely shaping of particle boundaries, resolving the particle shell, differentiating particle core and shell, and the effect of sample drying and staining. TEM without staining and cryo-TEM largely evaluate the core diameter. Negative staining TEM is more efficient than positive staining TEM to preserve native structure and to visualize the entire particle volume. However, no technique allows for a satisfactory imaging of both core and shell regions. The presence of long protruding chains is manifested by patched structure in cryo-TEM and a significant edge effect in SEM. This manuscript provides a basis for polymer chemists to develop their own specimen preparations and to tackle the interpretation of challenging systems.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Electron microscopy has proved to be a major tool to study the structure of self-assembled amphiphilic block copolymer particles. These specimens, like supramolecular biological structures, are problematic for electron microscopy because of their poor capacity to scatter electrons and their susceptibility to radiation damage and dehydration. Sub-50 nm core-shell spherical particles made up of poly(hydroxyethyl acrylate)-b-poly(styrene) are prepared via polymerization-induced self-assembly (PISA). For their morphological characterization, we discuss the advantages, limitations, and artefacts of TEM with or without staining, cryo-TEM, and SEM. A number of technical points are addressed such as precisely shaping of particle boundaries, resolving the particle shell, differentiating particle core and shell, and the effect of sample drying and staining. TEM without staining and cryo-TEM largely evaluate the core diameter. Negative staining TEM is more efficient than positive staining TEM to preserve native structure and to visualize the entire particle volume. However, no technique allows for a satisfactory imaging of both core and shell regions. The presence of long protruding chains is manifested by patched structure in cryo-TEM and a significant edge effect in SEM. This manuscript provides a basis for polymer chemists to develop their own specimen preparations and to tackle the interpretation of challenging systems. |
Chen, Hong; Noirbent, Guillaume; Sun, Ke; Brunel, Damien; Gigmes, Didier; Morlet-Savary, Fabrice; Zhang, Yijun; Liu, Shaohui; Xiao, Pu; Dumur, Frederic; Lalevee, Jacques Photoinitiators derived from natural product scaffolds: monochalcones in three-component photoinitiating systems and their applications in 3D printing (Article de journal) Polymer Chemistry, 11 (28), p. 4647–4659, 2020. @article{Chen2020, title = {Photoinitiators derived from natural product scaffolds: monochalcones in three-component photoinitiating systems and their applications in 3D printing}, author = { Hong Chen and Guillaume Noirbent and Ke Sun and Damien Brunel and Didier Gigmes and Fabrice Morlet-Savary and Yijun Zhang and Shaohui Liu and Pu Xiao and Frederic Dumur and Jacques Lalevee}, doi = {10.1039/d0py00568a}, year = {2020}, date = {2020-07-01}, journal = {Polymer Chemistry}, volume = {11}, number = {28}, pages = {4647--4659}, abstract = {The design and development of high-performance photoinitiating systems applicable to visible light delivered from light-emitting diodes (LEDs) attract ever-increasing attention due to their great potential applications in various fields. Chalcones belong to a well-established class of natural compounds present in many plants. In this context, photoinitiators based on the scaffolds of natural compounds have probably great potential to open the way for non-toxic photoinitiators in the manufacturing of biocompatible polymer materials. In this work, 23 different chalcones selected fromin silicomolecular design (i.e.through molecular orbital calculations) were used in conjunction with an aminei.e.ethyl 4-(dimethylamino) benzoate (EDB) and an iodonium salt (bis-(4-tert-butylphenyl)iodonium hexafluorophosphate, Iod) to form photoinitiating systems (PISs) capable of initiating the polymerization of polyethylene glycol (600) diacrylate (PEG-diacrylate)viaan oxidation-reduction reaction mechanism. The formation of hydrogels by the photopolymerization of PEG-acrylate is found to be very efficient. Remarkably, 10 of the 23 chalcones were completely new and even never synthesized prior to this work (chalcones4,5,7,8,9,10,12,15,16and21). By using computational quantum chemistry, fluorescence, steady-state photolysis, and electron spin resonance spin-trapping techniques, the photoinitiation mechanism of three-component photoinitiating systems based on chalcones/Iod/EDB is clarified. The results demonstrate that several chalcone-based PISs can initiate free radical photopolymerization. Moreover, the developed chalcone-based three-component systems are applied to generate 3D hydrogel patterns using the 3D laser write technology. This research provides some novel insights into photopolymerization reactions with three-component photoinitiating systems used for 3D printing of hydrogels.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The design and development of high-performance photoinitiating systems applicable to visible light delivered from light-emitting diodes (LEDs) attract ever-increasing attention due to their great potential applications in various fields. Chalcones belong to a well-established class of natural compounds present in many plants. In this context, photoinitiators based on the scaffolds of natural compounds have probably great potential to open the way for non-toxic photoinitiators in the manufacturing of biocompatible polymer materials. In this work, 23 different chalcones selected fromin silicomolecular design (i.e.through molecular orbital calculations) were used in conjunction with an aminei.e.ethyl 4-(dimethylamino) benzoate (EDB) and an iodonium salt (bis-(4-tert-butylphenyl)iodonium hexafluorophosphate, Iod) to form photoinitiating systems (PISs) capable of initiating the polymerization of polyethylene glycol (600) diacrylate (PEG-diacrylate)viaan oxidation-reduction reaction mechanism. The formation of hydrogels by the photopolymerization of PEG-acrylate is found to be very efficient. Remarkably, 10 of the 23 chalcones were completely new and even never synthesized prior to this work (chalcones4,5,7,8,9,10,12,15,16and21). By using computational quantum chemistry, fluorescence, steady-state photolysis, and electron spin resonance spin-trapping techniques, the photoinitiation mechanism of three-component photoinitiating systems based on chalcones/Iod/EDB is clarified. The results demonstrate that several chalcone-based PISs can initiate free radical photopolymerization. Moreover, the developed chalcone-based three-component systems are applied to generate 3D hydrogel patterns using the 3D laser write technology. This research provides some novel insights into photopolymerization reactions with three-component photoinitiating systems used for 3D printing of hydrogels. |
Tomal, Wiktoria; Pilch, Maciej; Chachaj-Brekiesz, Anna; Galek, Mariusz; Morlet-Savary, Fabrice; Graff, Bernadette; Dietlin, Cline; Lalevee, Jacques; Ortyl, Joanna Photoinitiator-catalyst systems based onmeta-terphenyl derivatives as photosensitisers of iodonium and thianthrenium salts for visible photopolymerization in 3D printing processes (Article de journal) Polymer Chemistry, 11 (28), p. 4604–4621, 2020. @article{Tomal2020, title = {Photoinitiator-catalyst systems based onmeta-terphenyl derivatives as photosensitisers of iodonium and thianthrenium salts for visible photopolymerization in 3D printing processes}, author = { Wiktoria Tomal and Maciej Pilch and Anna Chachaj-Brekiesz and Mariusz Galek and Fabrice Morlet-Savary and Bernadette Graff and Cline Dietlin and Jacques Lalevee and Joanna Ortyl}, doi = {10.1039/d0py00597e}, year = {2020}, date = {2020-07-01}, journal = {Polymer Chemistry}, volume = {11}, number = {28}, pages = {4604--4621}, abstract = {This work demonstrates a new versatile, efficient photoinitiating system based on 2-amino-4-phenyl-6-(4-phenylphenyl)benzene-1,3-dicarbonitrile and 2-amino-4-phenyl-6-[4-[(E)-styryl]phenyl]benzene-1,3-dicarbonitrile derivatives as photosensitisers of iodonium and thianthrenium salts for photopolymerization under visible low light intensity with potential translation to high performance 3D printing. The newmeta-terphenyl derivatives were characterised by standard analytical and spectroscopic techniques. The activity of new bimolecular photoinitiating systems was investigated using Fourier transform real-time infrared spectroscopy. As the choices for an efficient visible sensitiser are rather limited for thianthrenium salt, the syntheses of new photo-sensitisers have received considerable attention. Therefore, the main goal of this study was to applymeta-terphenyl derivatives as visible photosensitisers for different types of onium salts. For this purpose, the new 2-amino-4-phenyl-6-(4-phenylphenyl)benzene-1,3-dicarbonitrile and 2-amino-4-phenyl-6-[4-[(E)-styryl]phenyl]benzene-1,3-dicarbonitrile derivatives were combined with commercially available iodonium salt (HIP) and thianthrenium salt to create visible light photoinitiating systems. It was shown that the efficiency of these bimolecular photoinitiating systems was based on the favorable free energy change of the photoinduced electron transfer from themeta-terphenyl derivatives to the iodonium and thianthrenium salts. It was confirmed by the experiments that the ability of tested photoredox pairs to initiate the photopolymerization processes depends on the oxidation potentials of themeta-terphenyl derivatives and the reduction potentials of the onium salts. Here, we explore the role of the scientific aspects of the mechanism, energetics and dynamics of applicability of the newmeta-terphenyl compounds as efficient and versatile photosensitisers of onium salts with different oxidising power. Moreover, the investigated terphenyl derivatives can work as photoredox catalysts and efficient photoinitiating systems, and can be used with typical oxidation and reduction agents in both reductive and oxidation cycles.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work demonstrates a new versatile, efficient photoinitiating system based on 2-amino-4-phenyl-6-(4-phenylphenyl)benzene-1,3-dicarbonitrile and 2-amino-4-phenyl-6-[4-[(E)-styryl]phenyl]benzene-1,3-dicarbonitrile derivatives as photosensitisers of iodonium and thianthrenium salts for photopolymerization under visible low light intensity with potential translation to high performance 3D printing. The newmeta-terphenyl derivatives were characterised by standard analytical and spectroscopic techniques. The activity of new bimolecular photoinitiating systems was investigated using Fourier transform real-time infrared spectroscopy. As the choices for an efficient visible sensitiser are rather limited for thianthrenium salt, the syntheses of new photo-sensitisers have received considerable attention. Therefore, the main goal of this study was to applymeta-terphenyl derivatives as visible photosensitisers for different types of onium salts. For this purpose, the new 2-amino-4-phenyl-6-(4-phenylphenyl)benzene-1,3-dicarbonitrile and 2-amino-4-phenyl-6-[4-[(E)-styryl]phenyl]benzene-1,3-dicarbonitrile derivatives were combined with commercially available iodonium salt (HIP) and thianthrenium salt to create visible light photoinitiating systems. It was shown that the efficiency of these bimolecular photoinitiating systems was based on the favorable free energy change of the photoinduced electron transfer from themeta-terphenyl derivatives to the iodonium and thianthrenium salts. It was confirmed by the experiments that the ability of tested photoredox pairs to initiate the photopolymerization processes depends on the oxidation potentials of themeta-terphenyl derivatives and the reduction potentials of the onium salts. Here, we explore the role of the scientific aspects of the mechanism, energetics and dynamics of applicability of the newmeta-terphenyl compounds as efficient and versatile photosensitisers of onium salts with different oxidising power. Moreover, the investigated terphenyl derivatives can work as photoredox catalysts and efficient photoinitiating systems, and can be used with typical oxidation and reduction agents in both reductive and oxidation cycles. |
Daou, Jean T; Santos, Thomas Dos; Nouali, Habiba; Josien, Ludovic; Michelin, Laure; Pieuchot, Laurent; Dutournie, Patrick Synthesis of FAU-Type Zeolite Membranes with Antimicrobial Activity. (Article de journal) Molecules (Basel, Switzerland), 25 (15), 2020. @article{Daou2020, title = {Synthesis of FAU-Type Zeolite Membranes with Antimicrobial Activity.}, author = { T. Jean Daou and Thomas Dos Santos and Habiba Nouali and Ludovic Josien and Laure Michelin and Laurent Pieuchot and Patrick Dutournie}, doi = {10.3390/molecules25153414}, year = {2020}, date = {2020-07-01}, journal = {Molecules (Basel, Switzerland)}, volume = {25}, number = {15}, abstract = {In this study, a layer of a pure and dense phase of FAU-type zeolite was synthesized directly on the surface of alpha-Al2O3 plane macroporous support. Before hydrothermal synthesis, a step of cleaning of the support by an anionic detergent was performed, a roughness surface is created, allowing the anchoring of the zeolite nuclei and then their growth, favoring in this sense the formation of a homogeneous zeolite layer. The obtained membranes were fully characterized using X-ray diffraction analysis (XRD), nitrogen sorption, scanning electron microscopy (SEM), and mercury porosimetry. After 24 h of thermal treatment at 75 °C, a homogeneous zeolite layer composed of bipyramidal crystals of FAU-type zeolite is obtained with a thickness of about 2.5 m. No obvious defects or cracks can be observed. It was found that the increase in heating temperature could lead to the appearance of an impurity phase, GIS-type zeolite. Then the ideal zeolite membrane was exchanged with Ag+ or Zn2+ cations to studies their antimicrobial properties. Zeolites membranes exchanged with Ag+ showed an agar-diffusive bactericidal activity against gram negative Escherichia coli (E. coli) bacteria. Zn2+ exchanged zeolite membrane presented a bacteriostatic activity that is less diffusive in agar. As expected, non-exchanged zeolite membrane (in its Na+ form) have no effect on bacterial activity. This process is particularly interesting for the synthesis of a good quality FAU-type zeolite membranes with antimicrobial properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this study, a layer of a pure and dense phase of FAU-type zeolite was synthesized directly on the surface of alpha-Al2O3 plane macroporous support. Before hydrothermal synthesis, a step of cleaning of the support by an anionic detergent was performed, a roughness surface is created, allowing the anchoring of the zeolite nuclei and then their growth, favoring in this sense the formation of a homogeneous zeolite layer. The obtained membranes were fully characterized using X-ray diffraction analysis (XRD), nitrogen sorption, scanning electron microscopy (SEM), and mercury porosimetry. After 24 h of thermal treatment at 75 °C, a homogeneous zeolite layer composed of bipyramidal crystals of FAU-type zeolite is obtained with a thickness of about 2.5 m. No obvious defects or cracks can be observed. It was found that the increase in heating temperature could lead to the appearance of an impurity phase, GIS-type zeolite. Then the ideal zeolite membrane was exchanged with Ag+ or Zn2+ cations to studies their antimicrobial properties. Zeolites membranes exchanged with Ag+ showed an agar-diffusive bactericidal activity against gram negative Escherichia coli (E. coli) bacteria. Zn2+ exchanged zeolite membrane presented a bacteriostatic activity that is less diffusive in agar. As expected, non-exchanged zeolite membrane (in its Na+ form) have no effect on bacterial activity. This process is particularly interesting for the synthesis of a good quality FAU-type zeolite membranes with antimicrobial properties. |
Avila, Margarita Romero; Leon-Rojas, Andres Felipe; Lacroix, Pascal G; Malfant, Isabelle; Farfan, Norberto; Mhanna, Rana; Santillan, Rosa; Ramos-Ortiz, Gabriel; Malval, Jean-Pierre Two-Photon-Triggered NO Release via a Ruthenium-Nitrosyl Complex with a Star-Shaped Architecture. (Article de journal) The journal of physical chemistry letters, p. 6487–6491, 2020. @article{RomeroAvila2020, title = {Two-Photon-Triggered NO Release via a Ruthenium-Nitrosyl Complex with a Star-Shaped Architecture.}, author = { Margarita Romero Avila and Andres Felipe Leon-Rojas and Pascal G. Lacroix and Isabelle Malfant and Norberto Farfan and Rana Mhanna and Rosa Santillan and Gabriel Ramos-Ortiz and Jean-Pierre Malval}, doi = {10.1021/acs.jpclett.0c01953}, year = {2020}, date = {2020-07-01}, journal = {The journal of physical chemistry letters}, pages = {6487--6491}, abstract = {We report herein a molecular engineering strategy based on the design of a multipolar ruthenium-nitrosyl (Ru-NO) complex with a three-branched architecture. The three Ru-NO units are introduced at the periphery of a highly pi-delocalized truxene core bearing three terpyridine ligands. The two-photon absorption capabilities of the complex were investigated by the Z-scan technique. The strong electronic coupling among the individual arms gives rise to a very strong two-photon absorption response (delta800nm 1600 GM), which corresponds to a 16-fold enhancement of the capability of a single-arm reference, thereby promoting an efficient light-driven NO release process in aqueous media.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report herein a molecular engineering strategy based on the design of a multipolar ruthenium-nitrosyl (Ru-NO) complex with a three-branched architecture. The three Ru-NO units are introduced at the periphery of a highly pi-delocalized truxene core bearing three terpyridine ligands. The two-photon absorption capabilities of the complex were investigated by the Z-scan technique. The strong electronic coupling among the individual arms gives rise to a very strong two-photon absorption response (delta800nm 1600 GM), which corresponds to a 16-fold enhancement of the capability of a single-arm reference, thereby promoting an efficient light-driven NO release process in aqueous media. |
Dika, Ihab; Diot, Frederic; Bardinal, Veronique; Malval, Jean-Pierre; Ecoffet, Carole; Bruyant, Aurelien; Barat, David; Reig, Benjamin; Doucet, Jean-Baptiste; Camps, Thierry; Soppera, Olivier Near infraredphotopolymer for micro-optics applications (Article de journal) Journal of Polymer Science, 58 (13), p. 1796–1809, 2020. @article{Dika2020, title = {Near infraredphotopolymer for micro-optics applications}, author = { Ihab Dika and Frederic Diot and Veronique Bardinal and Jean-Pierre Malval and Carole Ecoffet and Aurelien Bruyant and David Barat and Benjamin Reig and Jean-Baptiste Doucet and Thierry Camps and Olivier Soppera}, doi = {10.1002/pol.20200106}, year = {2020}, date = {2020-07-01}, journal = {Journal of Polymer Science}, volume = {58}, number = {13}, pages = {1796--1809}, abstract = {Near infrared (NIR) activable photopolymers suitable for versatile fabrication of micro-optical elements were developed. The first main objective of this article is to show that these new photopolymers can be used for microfabrication and investigate the parameters governing the microfabrication process. The impact of photonic, physico-chemical, and chemical parameters is discussed. High quality microstructures with a good control over their size and shape are demonstrated. The second main objective is to show practical examples of microlenses and waveguides implemented on single core and multiple core optical fibers, VCSELs, and glass slides are then presented. The NIR photosensitivity of this negative tone photoresists allows using the device source itself as to start the crosslinking process, which constitutes a convenient approach for micro-optics self-positioning on NIR sources and justifies the interest of such NIR photopolymer for the fabrication micro-optical elements and optical interconnects.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Near infrared (NIR) activable photopolymers suitable for versatile fabrication of micro-optical elements were developed. The first main objective of this article is to show that these new photopolymers can be used for microfabrication and investigate the parameters governing the microfabrication process. The impact of photonic, physico-chemical, and chemical parameters is discussed. High quality microstructures with a good control over their size and shape are demonstrated. The second main objective is to show practical examples of microlenses and waveguides implemented on single core and multiple core optical fibers, VCSELs, and glass slides are then presented. The NIR photosensitivity of this negative tone photoresists allows using the device source itself as to start the crosslinking process, which constitutes a convenient approach for micro-optics self-positioning on NIR sources and justifies the interest of such NIR photopolymer for the fabrication micro-optical elements and optical interconnects. |
Azzaz, Ahmed Amine; Khiari, Besma; Jellali, Salah; Ghimbeu, Cam Elia Matei; Jeguirim, Mejdi Hydrochars production, characterization and application for wastewater treatment: A review (Article de journal) Renewable & Sustainable Energy Reviews, 127 , p. 109882, 2020. @article{Azzaz2020b, title = {Hydrochars production, characterization and application for wastewater treatment: A review}, author = { Ahmed Amine Azzaz and Besma Khiari and Salah Jellali and Cam Elia Matei Ghimbeu and Mejdi Jeguirim}, doi = {10.1016/j.rser.2020.109882}, year = {2020}, date = {2020-07-01}, journal = {Renewable & Sustainable Energy Reviews}, volume = {127}, pages = {109882}, abstract = {Hydrothermal carbonization (HTC) of wet solid wastes has been pointed out as an eco-friendly, flexible and highly efficient technology for the sustainable valorization of multiple sourced wastes. In this review paper, most recent studies on hydrochars (solid residue of the HTC process) production, characterization and application for wastewaters treatment was summarized and deeply discussed. The role of initial feedstock source nature and characteristics as well as the HTC experimental conditions including the temperature, the residence time and the pH media was assessed. Physical and chemical activation methods including the use of oxygen, steam, microwave, acids, alkaline, organics and salty solutions for the improvement of the physicochemical properties of the produced hydrochars are compared. The efficiency of these raw/modified hydrochars along with the involved mechanisms during organic (dyes) and mineral pollutants (heavy metals and nutrients) removal from aqueous solutions is also reviewed. Finally, this paper addresses the main challenges and also demonstrates insights on new directions for hydrochars research and development in the future.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hydrothermal carbonization (HTC) of wet solid wastes has been pointed out as an eco-friendly, flexible and highly efficient technology for the sustainable valorization of multiple sourced wastes. In this review paper, most recent studies on hydrochars (solid residue of the HTC process) production, characterization and application for wastewaters treatment was summarized and deeply discussed. The role of initial feedstock source nature and characteristics as well as the HTC experimental conditions including the temperature, the residence time and the pH media was assessed. Physical and chemical activation methods including the use of oxygen, steam, microwave, acids, alkaline, organics and salty solutions for the improvement of the physicochemical properties of the produced hydrochars are compared. The efficiency of these raw/modified hydrochars along with the involved mechanisms during organic (dyes) and mineral pollutants (heavy metals and nutrients) removal from aqueous solutions is also reviewed. Finally, this paper addresses the main challenges and also demonstrates insights on new directions for hydrochars research and development in the future. |
Duverger, Eric; Boyer, Anne-Gaelle; Sauriat-Dorizon, Helene; Sonnet, Philippe; Stephan, Regis; Hanf, Marie-Christine; Riedel, Damien Two-Dimensional Functionalized Ultrathin Semi-Insulating CaF2 Layer on the Si(100) Surface at a Low Temperature for Molecular Electronic Decoupling (Article de journal) Acs Applied Materials & Interfaces, 12 (26), p. 29661–29670, 2020. @article{Duverger2020, title = {Two-Dimensional Functionalized Ultrathin Semi-Insulating CaF2 Layer on the Si(100) Surface at a Low Temperature for Molecular Electronic Decoupling}, author = { Eric Duverger and Anne-Gaelle Boyer and Helene Sauriat-Dorizon and Philippe Sonnet and Regis Stephan and Marie-Christine Hanf and Damien Riedel}, doi = {10.1021/acsami.0c06631}, year = {2020}, date = {2020-07-01}, journal = {Acs Applied Materials & Interfaces}, volume = {12}, number = {26}, pages = {29661--29670}, abstract = {The ability to precisely control the electronic coupling/decoupling of adsorbates from surfaces is an essential goal. It is important for fundamental studies not only in surface science but also in several applied domains including, for example, miniaturized molecular electronic or for the development of various devices such as nanoscale biosensors or photovoltaic cells. Here, we provide atomic-scale experimental and theoretical investigations of a semi-insulating layer grown on a silicon surface via its epitaxy with CaF2. We show that, following the formation of a wetting layer, the ensuing organized unit cells are coupled to additional physisorbed CaF2 molecules, periodically located in their surroundings. This configuration shapes the formation of ribbons of stripes that functionalize the semiconductor surface. The obtained assembly, having a monolayer thickness, reveals a surface gap energy of similar to 3.2 eV. The adsorption of iron tetraphenylporphyrin molecules on the ribbons of stripes is used to estimate the electronic insulating properties of this structure via differential conductance measurements. Density functional theory (DFT) including several levels of complexity (annealing, DFT + U, and nonlocal van der Waals functionals) is employed to reproduce our experimental observations. Our findings offer a unique and robust template that brings an alternative solution to electronic semi-insulating layers on metal surfaces such as NaCl. Hence, CaF2/Si(100) ribbon of stripe structures, whose lengths can reach more than 100 nm, can be used as a versatile surface platform for various atomic-scale studies of molecular devices.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The ability to precisely control the electronic coupling/decoupling of adsorbates from surfaces is an essential goal. It is important for fundamental studies not only in surface science but also in several applied domains including, for example, miniaturized molecular electronic or for the development of various devices such as nanoscale biosensors or photovoltaic cells. Here, we provide atomic-scale experimental and theoretical investigations of a semi-insulating layer grown on a silicon surface via its epitaxy with CaF2. We show that, following the formation of a wetting layer, the ensuing organized unit cells are coupled to additional physisorbed CaF2 molecules, periodically located in their surroundings. This configuration shapes the formation of ribbons of stripes that functionalize the semiconductor surface. The obtained assembly, having a monolayer thickness, reveals a surface gap energy of similar to 3.2 eV. The adsorption of iron tetraphenylporphyrin molecules on the ribbons of stripes is used to estimate the electronic insulating properties of this structure via differential conductance measurements. Density functional theory (DFT) including several levels of complexity (annealing, DFT + U, and nonlocal van der Waals functionals) is employed to reproduce our experimental observations. Our findings offer a unique and robust template that brings an alternative solution to electronic semi-insulating layers on metal surfaces such as NaCl. Hence, CaF2/Si(100) ribbon of stripe structures, whose lengths can reach more than 100 nm, can be used as a versatile surface platform for various atomic-scale studies of molecular devices. |
Bruneau, Marion; Brendle, Jocelyne; Bennici, Simona; Limousy, Lionel; Pluchon, Sylvain Talc-like hybrids: influence of the synthesis (Article de journal) New Journal of Chemistry, 44 (25), p. 10326–10333, 2020. @article{Bruneau2020, title = {Talc-like hybrids: influence of the synthesis}, author = { Marion Bruneau and Jocelyne Brendle and Simona Bennici and Lionel Limousy and Sylvain Pluchon}, doi = {10.1039/c9nj06298j}, year = {2020}, date = {2020-07-01}, journal = {New Journal of Chemistry}, volume = {44}, number = {25}, pages = {10326--10333}, abstract = {This study aims to understand how the synthesis parameters influence the formation of organic-inorganic hybrids having a talc like structure synthesized usingN-[3-(trimethoxysilyl)propyl]ethylenediamine as the silicon source. The hybrids have been analysed mainly by(29)Si solid-state NMR in order to access the condensation degree of the silicon species. The results have shown that the solvent and the synthesis duration have no influence on the condensation. The addition of water in the synthesis medium induces a strong decrease of the degree of polycondensation of the silicon species. A basic pH of the synthesis medium can also further decrease this parameter. Additional information has been provided by X-Ray Diffraction and Thermogravimetric analysis which allow highlighting a correlation between the Full Width at Half Maximum and the thermal stability of the hybrids synthesized in the presence of different amounts of water. This opens the possibility of modulating the polycondensation degree of the silicic species, the crystallinity and the thermal stability changing only one parameter.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This study aims to understand how the synthesis parameters influence the formation of organic-inorganic hybrids having a talc like structure synthesized usingN-[3-(trimethoxysilyl)propyl]ethylenediamine as the silicon source. The hybrids have been analysed mainly by(29)Si solid-state NMR in order to access the condensation degree of the silicon species. The results have shown that the solvent and the synthesis duration have no influence on the condensation. The addition of water in the synthesis medium induces a strong decrease of the degree of polycondensation of the silicon species. A basic pH of the synthesis medium can also further decrease this parameter. Additional information has been provided by X-Ray Diffraction and Thermogravimetric analysis which allow highlighting a correlation between the Full Width at Half Maximum and the thermal stability of the hybrids synthesized in the presence of different amounts of water. This opens the possibility of modulating the polycondensation degree of the silicic species, the crystallinity and the thermal stability changing only one parameter. |
Telitel, Siham; Morris, Jason C; Guillaneuf, Yohann; Clement, Jean-Louis; Morlet-Savary, Fabrice; Spangenberg, Arnaud; Malval, Jean-Pierre; Lalevee, Jacques; Gigmes, Didier; Soppera, Olivier Laser Direct Writing of Arbitrary Complex Polymer Microstructures by Nitroxide-Mediated Photopolymerization. (Article de journal) ACS applied materials & interfaces, 12 (27), p. 30779–30786, 2020. @article{Telitel2020, title = {Laser Direct Writing of Arbitrary Complex Polymer Microstructures by Nitroxide-Mediated Photopolymerization.}, author = { Siham Telitel and Jason C. Morris and Yohann Guillaneuf and Jean-Louis Clement and Fabrice Morlet-Savary and Arnaud Spangenberg and Jean-Pierre Malval and Jacques Lalevee and Didier Gigmes and Olivier Soppera}, doi = {10.1021/acsami.0c06339}, year = {2020}, date = {2020-07-01}, journal = {ACS applied materials & interfaces}, volume = {12}, number = {27}, pages = {30779--30786}, abstract = {In this paper, we demonstrate the possibility of generating arbitrary polymer microstructures covalently linked to a first polymer layer by laser direct writing. At the molecular scale, the process relies on nitroxide-mediated photopolymerization triggered by a light-sensitive alkoxyamine. In addition to the proof of concept and examples of achievable structures, including multichemistry patterns and 3D structures, this paper aims at investigating the physicochemical phenomena involved under such conditions. In particular, the parameters influencing the repolymerization process are considered, and special attention is paid to the study of the impact of oxygen on the spatial control of the polymerization. Such a work opens many possibilities toward the fabrication of on-demand high-resolution (multi)functional polymer micro and nanostructures.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this paper, we demonstrate the possibility of generating arbitrary polymer microstructures covalently linked to a first polymer layer by laser direct writing. At the molecular scale, the process relies on nitroxide-mediated photopolymerization triggered by a light-sensitive alkoxyamine. In addition to the proof of concept and examples of achievable structures, including multichemistry patterns and 3D structures, this paper aims at investigating the physicochemical phenomena involved under such conditions. In particular, the parameters influencing the repolymerization process are considered, and special attention is paid to the study of the impact of oxygen on the spatial control of the polymerization. Such a work opens many possibilities toward the fabrication of on-demand high-resolution (multi)functional polymer micro and nanostructures. |
Ge, Dandan; Marguet, Sylvie; Issa, Ali; Jradi, Safi; Nguyen, Tien Hoa; Nahra, Mackrine; Beal, Jeremie; Deturche, Regis; Chen, Hongshi; Blaize, Sylvain; Plain, Jerome; Fiorini, Celine; Douillard, Ludovic; Soppera, Olivier; Dinh, Xuan Quyen; Dang, Cuong; Yang, Xuyong; Xu, Tao; Wei, Bin; Sun, Xiao Wei; Couteau, Christophe; Bachelot, Renaud Hybrid plasmonic nano-emitters with controlled single quantum emitter positioning on the local excitation field. (Article de journal) Nature communications, 11 (1), p. 3414–3414, 2020. @article{Ge2020b, title = {Hybrid plasmonic nano-emitters with controlled single quantum emitter positioning on the local excitation field.}, author = { Dandan Ge and Sylvie Marguet and Ali Issa and Safi Jradi and Tien Hoa Nguyen and Mackrine Nahra and Jeremie Beal and Regis Deturche and Hongshi Chen and Sylvain Blaize and Jerome Plain and Celine Fiorini and Ludovic Douillard and Olivier Soppera and Xuan Quyen Dinh and Cuong Dang and Xuyong Yang and Tao Xu and Bin Wei and Xiao Wei Sun and Christophe Couteau and Renaud Bachelot}, doi = {10.1038/s41467-020-17248-8}, year = {2020}, date = {2020-07-01}, journal = {Nature communications}, volume = {11}, number = {1}, pages = {3414--3414}, abstract = {Hybrid plasmonic nano-emitters based on the combination of quantum dot emitters (QD) and plasmonic nanoantennas open up new perspectives in the control of light. However, precise positioning of any active medium at the nanoscale constitutes a challenge. Here, we report on the optimal overlap of antenna's near-field and active medium whose spatial distribution is controlled via a plasmon-triggered 2-photon polymerization of a photosensitive formulation containing QDs. Au nanoparticles of various geometries are considered. The response of these hybrid nano-emitters is shown to be highly sensitive to the light polarization. Different light emission states are evidenced by photoluminescence measurements. These states correspond to polarization-sensitive nanoscale overlap between the exciting local field and the active medium distribution. The decrease of the QD concentration within the monomer formulation allows trapping of a single quantum dot in the vicinity of the Au particle. The latter objects show polarization-dependent switching in the single-photon regime.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hybrid plasmonic nano-emitters based on the combination of quantum dot emitters (QD) and plasmonic nanoantennas open up new perspectives in the control of light. However, precise positioning of any active medium at the nanoscale constitutes a challenge. Here, we report on the optimal overlap of antenna's near-field and active medium whose spatial distribution is controlled via a plasmon-triggered 2-photon polymerization of a photosensitive formulation containing QDs. Au nanoparticles of various geometries are considered. The response of these hybrid nano-emitters is shown to be highly sensitive to the light polarization. Different light emission states are evidenced by photoluminescence measurements. These states correspond to polarization-sensitive nanoscale overlap between the exciting local field and the active medium distribution. The decrease of the QD concentration within the monomer formulation allows trapping of a single quantum dot in the vicinity of the Au particle. The latter objects show polarization-dependent switching in the single-photon regime. |
Choo, Min-Yee; Oi, Lee Eng; Daou, Jean T; Ling, Tau Chuan; Lin, Yu-Chuan; Centi, Gabriele; Ng, Eng-Poh; Juan, Joon Ching Deposition of NiO Nanoparticles on Nanosized Zeolite NaY for Production of Biofuel via Hydrogen-Free Deoxygenation. (Article de journal) Materials (Basel, Switzerland), 13 (14), 2020. @article{Choo2020, title = {Deposition of NiO Nanoparticles on Nanosized Zeolite NaY for Production of Biofuel via Hydrogen-Free Deoxygenation.}, author = { Min-Yee Choo and Lee Eng Oi and T. Jean Daou and Tau Chuan Ling and Yu-Chuan Lin and Gabriele Centi and Eng-Poh Ng and Joon Ching Juan}, doi = {10.3390/ma13143104}, year = {2020}, date = {2020-07-01}, journal = {Materials (Basel, Switzerland)}, volume = {13}, number = {14}, abstract = {Nickel-based catalysts play an important role in the hydrogen-free deoxygenation for the production of biofuel. The yield and quality of the biofuel are critically affected by the physicochemical properties of NiO supported on nanosized zeolite Y (Y65, crystal size of 65 nm). Therefore, 10 wt% NiO supported on Y65 synthesized by using impregnation (IM) and deposition-precipitation (DP) methods were investigated. It was found that preparation methods have a significant effect on the deoxygenation of triolein. The initial rate of the DP method (14.8 goil·h-1) was 1.5 times higher than that of the IM method (9.6 goil·h-1). The DP-Y65 showed the best deoxygenation performance with a 80.0% conversion and a diesel selectivity of 93.7% at 380 °C within 1 h. The outstanding performance from the DP method was due to the smaller NiO particle size (3.57 ± 0.40 nm), high accessibility (H.F value of 0.084), and a higher Bronsted to Lewis acidity (B/L) ratio (0.29), which has improved the accessibility and deoxygenation ability of the catalyst. The NH4+ released from the decomposition of the urea during the DP process increased the B/L ratio of zeolite NaY. As a result, the pretreatment to convert Na-zeolite to H-zeolite in a conventional zeolite synthesis can be avoided. In this regard, the DP method offers a one-pot synthesis to produce smaller NiO-supported nanosized zeolite NaY with a high B/L ratio, and it managed to produce a higher yield with selectivity towards green diesel via deoxygenation under a hydrogen-free condition.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Nickel-based catalysts play an important role in the hydrogen-free deoxygenation for the production of biofuel. The yield and quality of the biofuel are critically affected by the physicochemical properties of NiO supported on nanosized zeolite Y (Y65, crystal size of 65 nm). Therefore, 10 wt% NiO supported on Y65 synthesized by using impregnation (IM) and deposition-precipitation (DP) methods were investigated. It was found that preparation methods have a significant effect on the deoxygenation of triolein. The initial rate of the DP method (14.8 goil·h-1) was 1.5 times higher than that of the IM method (9.6 goil·h-1). The DP-Y65 showed the best deoxygenation performance with a 80.0% conversion and a diesel selectivity of 93.7% at 380 °C within 1 h. The outstanding performance from the DP method was due to the smaller NiO particle size (3.57 ± 0.40 nm), high accessibility (H.F value of 0.084), and a higher Bronsted to Lewis acidity (B/L) ratio (0.29), which has improved the accessibility and deoxygenation ability of the catalyst. The NH4+ released from the decomposition of the urea during the DP process increased the B/L ratio of zeolite NaY. As a result, the pretreatment to convert Na-zeolite to H-zeolite in a conventional zeolite synthesis can be avoided. In this regard, the DP method offers a one-pot synthesis to produce smaller NiO-supported nanosized zeolite NaY with a high B/L ratio, and it managed to produce a higher yield with selectivity towards green diesel via deoxygenation under a hydrogen-free condition. |
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