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See detailPreparation of chitosan-based nanofibers with multilayered structure
Croisier, Florence ULg; Duwez, Anne-Sophie ULg; Dijkstra, P. J. et al

Conference (2011, May 12)

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See detailPreparation of CMI-1 supported H3+xPMo12-xVxO40 for the selective oxidation of propylene
Benadji, S.; Eloy, P.; Léonard, Alexandre ULg et al

in Studies in Surface Science and Catalysis (2010), 175

Catalysts, comprising 30 wt.% of heteropolyacids (HPAs) H 3+xPMo 12-xV xO 40 (x = 0-3) supported on a mesoporous material CMI-1 by dry impregnation were characterized by several techniques. Their ... [more ▼]

Catalysts, comprising 30 wt.% of heteropolyacids (HPAs) H 3+xPMo 12-xV xO 40 (x = 0-3) supported on a mesoporous material CMI-1 by dry impregnation were characterized by several techniques. Their catalytic performances were compared to those of bulk HPAs in the propylene oxidation by molecular oxygen at 350°C. The supported HPAs exhibit higher catalytic activity in propylene oxidation than the bulk ones and favoured the formation of acrolein, acetaldehyde and acetic acid, compared to the mother catalysts which lead only to the formation of COx. The enhanced oxidation catalytic activity of supported systems was attributed to the fine dispersion of H 3+xPMo 12-xVxO 40 species on the CMI-1 mesoporous material via physical adsorption, together with the fact that the structure of both CMI-1 and HPAs remained intact during the impregnation. © 2010 Elsevier B.V. All rights reserved. [less ▲]

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See detailPreparation of cross-linked chitosan-based nanofibers as wound dressing
Aqil, Abdelhafid ULg; Ziani, K.; Tchemtchoua Tateu, Victor ULg et al

Poster (2009, November 18)

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See detailPreparation of drug-loaded scaffolds for biomedical applications using supercritical carbon dioxide technology
Champeau, Mathilde; Jérôme, Christine ULg; Tassaing, Thierry

Conference (2012, March 25)

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See detailPreparation of drug-loaded scaffolds for biomedical applications using supercritical fluid technology
Champeau, Mathilde; Jérôme, Christine ULg; Tassaing, Thierry

Conference (2013, March 17)

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See detailPreparation of fire-resistant poly(styrene-co-acrylonitrile) foams using supercritical CO2 technology
Urbanczyk, Laetitia ULg; Bourbigot, Serge; Calberg, Cédric ULg et al

in Journal of Materials Chemistry (2010), 20

This work deals with the preparation and characterization of fire-resistant poly(styrene coacrylonitrile) (SAN) foams containing (organo)clays and/or melamine polyphosphate (MPP) as fire retardants using ... [more ▼]

This work deals with the preparation and characterization of fire-resistant poly(styrene coacrylonitrile) (SAN) foams containing (organo)clays and/or melamine polyphosphate (MPP) as fire retardants using supercritical CO2 as the foaming agent. The additives dispersion was first characterized with X-ray and transmission electron microscopy (TEM) analyses. Their presence clearly affected the cellular morphology, as observed by scanning electron microscopy (SEM). Then, the peak of heat release rate (PHRR) and total heat evolved (THE) were determined with a cone calorimetry test, performed on each foamed sample as a function of the foam density. Incorporation of clay (3 and 5 wt%) in the exfoliated state into the SAN foam clearly led to a significant decrease of PHRR, while intercalated and aggregated clay had a lower effect. Similar results were obtained with 10 and 20 wt% of MPP. The best results were obtained when exfoliated clay and MPP were combined, with a PHRR drop as large as 75%, thanks to the synergistic action of both additives. The magnitude of PHRR drop, related to the fire resistance, was found to be in direct relationship with the cohesiveness of the protective carbonaceous layer formed at the sample surface during combustion. Clay and MPP, when added together, are thus believed to favour the formation of a highly cohesive protective layer able to act as an efficient shield against the flame, despite the fact that the sample is originally composed of ~90% of voids. [less ▲]

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See detailPreparation of functionalized alkoxyamine initiator and its use
Detrembleur, Christophe ULg; Gross, Thomas; Meyer, Rolf-Volker

Patent (2004)

A one-pot process for the preparation of functional alkoxyamines of the general formula (I),is disclosed. The process entails (1) reacting an oxidizing agent with a sterically hindered secondary amine to ... [more ▼]

A one-pot process for the preparation of functional alkoxyamines of the general formula (I),is disclosed. The process entails (1) reacting an oxidizing agent with a sterically hindered secondary amine to produce an aqueous phase and a nitroxyl radical (2) removing the aqueous phase and adding to the nitroxyl radical one or more vinyl monomer(s) conforming to a formula and a system which produces free radicals. Also disclosed is a process of polymerizing monomers using the functional alkoxyamine. [less ▲]

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See detailPreparation of functionalized alkoxyamine initiator and its use
Detrembleur, Christophe ULg; Gross, Thomas; Meyer, Rolf-Volker

Patent (2003)

A one-pot process for the preparation of functional alkoxyamines of the general formula (I), is disclosed. The process entails (1) reacting an oxidizing agent with a sterically hindered secondary amine to ... [more ▼]

A one-pot process for the preparation of functional alkoxyamines of the general formula (I), is disclosed. The process entails (1) reacting an oxidizing agent with a sterically hindered secondary amine to produce an aqueous phase and a nitroxyl radical (2) removing the aqueous phase and adding to the nitroxyl radical one or more vinyl monomer(s) conforming to a formula and a system which produces free radicals. Also disclosed is a process of polymerizing monomers using the functional alkoxyamine. [less ▲]

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See detailThe preparation of functionalized alkoxyamine initiator and its use
Detrembleur, Christophe ULg; Gross, Thomas; Meyer, Rolf-Volker

Patent (2003)

A one-pot process for the preparation of functional alkoxyamines of the general formula (I), (See Formula I) is disclosed. The process entails (1) reacting an oxidizing agent with a sterically hindered ... [more ▼]

A one-pot process for the preparation of functional alkoxyamines of the general formula (I), (See Formula I) is disclosed. The process entails (1) reacting an oxidizing agent with a sterically hindered secondary amine to produce an aqueous phase and a nitroxyl radical (2) removing the aqueous phase and adding to the nitroxyl radical one or more vinyl monomer(s) conforming to a formula and a system which produces free radicals . Also disclosed is a process of polymerizing monomers using the function al alkoxyamine. [less ▲]

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See detailPreparation of highly ordered CMI-1 and wormhole-like DWM mesoporous silica catalyst supports using C 16(EO) 10 as surfactant
Léonard, Alexandre ULg; Blin, J.-L.; Su, B.-L.

in Studies in Surface Science and Catalysis (2002), 143

Concentrations of polyoxyethylene alkyl ether surfactants located in the hexagonal H1 micellar domain typically afford disordered mesoporous structures of wormhole-like channels after polymerization of ... [more ▼]

Concentrations of polyoxyethylene alkyl ether surfactants located in the hexagonal H1 micellar domain typically afford disordered mesoporous structures of wormhole-like channels after polymerization of the inorganic precursor in solution. The effect of hydrothermal treatment duration and temperature on the characteristics of the obtained disordered DWM (Disordered Wormhole-like Mesostructure) compounds has been investigated. Thermal stability of these samples has also been studied and appears to be superior to that of MCM-41 type materials. If the weight percentage of surfactant in solution is however decreased, well-ordered hexagonal CMI-1 can be directly obtained. In this case, a co-operative mechanism leading to spherical particles of organized channel structures has been proposed. Influence of the surfactant concentration on the arrangement has been discussed in detail. [less ▲]

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See detailPreparation of living polymer microspheres by dispersion atom transfer radical polymerization in scCO2 using fluorinated macroligands
Grignard, Bruno ULg; Calberg, Cédric ULg; Jérôme, Christine ULg et al

Poster (2009, May 19)

Due to an increasing need for polymers with well-defined architecture (diblock-, graft-, star-shaped copolymers), molecular weight and/or functional end-groups, the use of controlled radical ... [more ▼]

Due to an increasing need for polymers with well-defined architecture (diblock-, graft-, star-shaped copolymers), molecular weight and/or functional end-groups, the use of controlled radical polymerization (CRP) in scCO2 has started to gain attention. Among all the controlled processes, Atom Transfer Radical Polymerization has emerged as a robust tool for the preparation of polymers with well-defined molecular weight, architecture and chain-end functionality. In a very recent paper, we reported the first efficient dispersion ATRP of methyl methacrylate (MMA) in scCO2 using a fluorinated polymeric ligand that had a dual role, i.e., the complexation of the copper salt and the stabilization of PMMA growing particles. In this contribution, we extended this new system to the dispersion ATRP of styrene, to the synthesis of diblock copolymers beads and the controlled synthesis of hyperbranched copolymers. Finally, because both ATRP and alkyne-azide Huisgen’s 1,3-dipolar cycloaddition relies on the use of a Cu(I) catalyst, synthesis of pyrene end-functionalized polymers by simultaneous dispersion ATRP and click reaction was also investigated in supercritical carbon dioxide. [less ▲]

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See detailPreparation of low-density xerogels by incorporation of additives during synthesis
Alié, Christelle ULg; Ferauche, Fabrice; Pirard, René ULg et al

in Journal of Non-Crystalline Solids (2001), 289(1-3), 88-96

Low-density xerogels were prepared by incorporation of an additive to alcogels prior to gelation. The additives studied are 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS), 3 ... [more ▼]

Low-density xerogels were prepared by incorporation of an additive to alcogels prior to gelation. The additives studied are 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS), 3-aminopropyltrimethoxysilane (AMS), propyltrimethoxysilane (PMS), tetramethylorthosilicate (TMOS) and 3-aminopropyltriethoxysilane (AES) using tetraethylorthosilicate (TEOS) as main silica precursor. Samples were also prepared with EDAS as additive and TMOS as main silica reagent. When the additive contains methoxy groups, it reacts first, forms nuclei on which the main reagent TEOS reacts to form the silica particles. The nucleation mechanism by the additive occurs only in case of a difference of reactivity between additive and main silica precursor. The other group of the additive (amine, alkyl group, ...) influences only the gelation time. In case of ethoxy groups (series AES/TEOS) or methoxy groups (series EDAS/TMOS) for both additive and main reagent, there is no nucleation by the additive. (C) 2001 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailPreparation of low-density xerogels from mixtures of TEOS with substituted alkoxysilanes. I. O-17 NMR study of the hydrolysis-condensation process
Alié, Christelle ULg; Pirard, Jean-Paul ULg

in Journal of Non-Crystalline Solids (2003), 320(1-3), 21-30

Low-density xerogels were synthesised by incorporation of an additive to base catalysed tetraethylorthosilicate (TEOS) alcogels directly during the preparation of the sol. The nucleation mechanism by the ... [more ▼]

Low-density xerogels were synthesised by incorporation of an additive to base catalysed tetraethylorthosilicate (TEOS) alcogels directly during the preparation of the sol. The nucleation mechanism by the additive was established by experiments during sol-gel transition. O-17 NMR spectroscopy on TEOS-ethanol-water, 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS)-ethanol-water and EDAS-TEOS-ethanol-water solutions shows that the hydrolysis-condensation of EDAS is much faster than that of TEOS. Consequently it can be assumed that EDAS forms nuclei, onto which TEOS condenses later to form the silica particles. (C) 2003 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailPreparation of low-density xerogels from mixtures of TEOS with substituted alkoxysilanes. II. Viscosity study of the sol-gel transition
Alié, Christelle ULg; Pirard, René ULg; Pirard, Jean-Paul ULg

in Journal of Non-Crystalline Solids (2003), 320(1-3), 31-39

Mixtures of TEOS with substituted methoxysilanes generate low-density xerogels due to a nucleation mechanism involving the substituted alkoxysilane. The sol-gel transition of these mixtures was followed ... [more ▼]

Mixtures of TEOS with substituted methoxysilanes generate low-density xerogels due to a nucleation mechanism involving the substituted alkoxysilane. The sol-gel transition of these mixtures was followed by theological characterisation. The transition from sol to gel takes place in a few minutes at ambient temperature. For the series exhibiting nucleation by the additive. the gel time goes through a slight minimum when the ratio of additive/main reagent increases. The elastic modulus increases with increasing ratio of additive/main reagent as the particle size decreases because of the nucleation mechanism by the additive. Samples with smaller particles exhibit the highest modulus for equal silica concentrations. (C) 2003 Elsevier Science B.V. All rights reserved. [less ▲]

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