References of "e-Polymers"
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See detailAntimicrobial activity of polyestyrene particles coated by photo-crooslinked block copolymers containing a biocidal polymethacrylate block
Lenoir, Sandrine ULg; Pagnoulle, Christophe; Detrembleur, Christophe ULg et al

in e-Polymers (2005), 74

A commercially available poly(ethylene-co-butylene) copolymer, end-capped by a short polyisoprene block and a hydroxyl group (PI-b-PEB-OH), has been derivatized into a macroinitiator for atom transfer ... [more ▼]

A commercially available poly(ethylene-co-butylene) copolymer, end-capped by a short polyisoprene block and a hydroxyl group (PI-b-PEB-OH), has been derivatized into a macroinitiator for atom transfer radical polymerization (ATRP) by esterification of the hydroxyl end-group by an activated bromide-containing acyl bromide. Two types of triblock copolymers, Pl-b-PEB-b-poly(dimethylaminoethyl methacrylate) (PDMAEMA) and Pl-b-PEB-b-poly[2-(tert-butylamino)ethyl methacrylate] (PTBAEMA), have been synthesized and used to coat polystyrene particles. These coatings have been permanently immobilized by UV cross-linking of the isoprene units. They exhibit a biocidal activity against Gram-negative bacteria either intrinsically in case of the PTBAEMA block or upon quaternization of the PDMAEMA block by octyl bromide. The antimicrobial activity is directly related to the concentration of coated PS particles in the medium. [less ▲]

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See detailWetting of bioactive glass surfaces by poly(alpha-hydroxyacid) melts: interaction between Bioglass (R) and biodegradable polymers
Blaker, Jonny J.; Maquet, Véronique; Boccaccini, Aldo R. et al

in e-Polymers (2005), 23

The interfacial characteristics between bioactive glass (4555 Bioglass(R)) surfaces and poly(alpha-hydroxyacid) melts have been assessed by direct wetting measurements. In particular, the wettability of ... [more ▼]

The interfacial characteristics between bioactive glass (4555 Bioglass(R)) surfaces and poly(alpha-hydroxyacid) melts have been assessed by direct wetting measurements. In particular, the wettability of Bioglass(R) powder by poly(D,L-lactide) (PDLLA) and poly(D,L-lactide-co-glycolide) (PLGA) was assessed by imbibition measurements. Additionally, the equilibrium contact angles of PDLLA and PLGA melts on a sintered Bioglass(R) surface were measured. The surface energy of the bioactive glass and the polymers was determined from contact angles measured using various test liquids on PDLLA, PLGA and Bioglass(R) solid substrates. There are sufficient adhesive interactions between the polymers and Bioglass(R). A simple heat treatment of the bioactive glass in an inert gas atmosphere leads to an improved wetting behaviour, indicating increased adhesive interactions. Scanning electron micrographs of the polymer+Bioglass(R) composites formed by polymer penetration into the powder bed show the formation of a 'good quality' interface. [less ▲]

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See detailElectrodeposition of mixed adherent thin films of poly(ethyl acrylate) and polyacrylonitrile onto nickel
Baute, Noëlle; Geskin, Victor M; Lazzaroni, Roberto et al

in e-Polymers (2004), (63), 1-20

Adherent thin polymer films have been prepared by sequential electrodeposition of ethyl acrylate (EA) and acrylonitrile (AN) onto nickel. Their composition has been studied by IR spectroscopy and time of ... [more ▼]

Adherent thin polymer films have been prepared by sequential electrodeposition of ethyl acrylate (EA) and acrylonitrile (AN) onto nickel. Their composition has been studied by IR spectroscopy and time of flight-secondary ion mass spectrometry. Morphology and thickness have been analyzed by atomic force microscopy and ellipsometry, respectively, and compared to single component films of PEA and PAN. No microphase separation was detected in the mixed PEA/PAN films. These show a granular morphology comparable to that of PAN films. The grains contain the two constitutive polymers, as confirmed by the selective thermal degradation of PEA. [less ▲]

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See detailNafion-layered silicate nanocomposite membrane for fuel cell application
Thomassin, Jean-Michel ULg; Pagnoulle, Christophe; Bizzari, Didier et al

in e-Polymers (2004), (18), 1-13

Direct methanol fuel cells (DMFCs) using a proton exchange membrane as electrolyte is an attractive option for electricity generation. The most widely used membrane in the DMFC system is based on a ... [more ▼]

Direct methanol fuel cells (DMFCs) using a proton exchange membrane as electrolyte is an attractive option for electricity generation. The most widely used membrane in the DMFC system is based on a perfluorinated polymer bearing sulfonic acid functions like Nafion®. The latter combines chemical, mechanical and thermal stability and high protonic conductivity but shows elevated methanol permeability. We propose the preparation of a novel type of hybrid membranes to tentatively solve this problem. This innovative material results from the homogeneous dispersion of a nano-scaled inorganic filler within Nafion. The filler consists of stacks of negatively charged alumino-silicate layers (Cloisite), with a positive counter-ion in the interlamellar space. The purpose of the addition of this filler is to decrease methanol diffusion through the polymer membrane without decreasing too much the ionic conductivity. [less ▲]

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See detailNew ruthenium catalysts bearing N-heterocyclic carbene ligands for ATRA and ATRP
Sauvage, Xavier ULg; Richel, Aurore ULg; Delfosse, Sébastien et al

in e-polymers (2003)

This study provides a glimpse of the synthetic possibilities arising from the use of NHC􀀀 s complexes in radical reactions, and illustrates how the fine tuning of the steric and electronic parameters of ... [more ▼]

This study provides a glimpse of the synthetic possibilities arising from the use of NHC􀀀 s complexes in radical reactions, and illustrates how the fine tuning of the steric and electronic parameters of this class of ruthenium complexes affect their catalytic activity. [less ▲]

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See detailRuthenium alkylidenes: a new class of catalysts for Kharasch addition and controlled radical polymerisation of vinyl monomers
Delfosse, Sébastien; Richel, Aurore ULg; Demonceau, Albert ULg et al

in e-polymers (2003)

Air-stable and readily available ruthenium benzylidene complexes of the general type (RuCl2 (=CHPh)(L)(L')) (L, L' = P(cC5H9)3, PCy3 and/or a N-heterocyclic carbene) constitute a new class of catalyst ... [more ▼]

Air-stable and readily available ruthenium benzylidene complexes of the general type (RuCl2 (=CHPh)(L)(L')) (L, L' = P(cC5H9)3, PCy3 and/or a N-heterocyclic carbene) constitute a new class of catalyst precursors for atom transfer radical addition (ATRA, also called Kharasch addition) and atom transfer radical polymerisation (ATRP) of methyl methacrylate and styrene, and provide an unprecedented example for the involvement of ruthenium alkylidenes in radical reactions. They promote the addition of carbon tetrachloride to methyl methacrylate and styrene in moderate to high yield (Table 1). They also promote the polymerisation of methyl methacrylate and styrene in a controlled way with good to excellent yields (Table 2). The ligands L (P(cC5H9)3, PCy3 and/or a N-heterocyclic carbene) play a particularly important role in determining the rate of the polymerisation. A similarly pronounced influence is exerted by the substituents on the N-heterocyclic carbene. Our results indicate that: 􀀀 The catalysts decompose quickly under ATRA and ATRP conditions; 􀀀 Polymerisations are mediated by both (RuCl2(=CHPh)(L)(L')) complexes and ruthenium species bereft of the benzylidene moiety. [less ▲]

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See detailNew ruthenium catalysts bearing N-heterocyclic carbene ligands for ATRP
Tudose, Adriana; Delfosse, Sébastien; Richel, Aurore ULg et al

in e-polymers (2003)

New ruthenium catalysts bearing N-heterocyclic carbene ligands in Kharasch chemistry

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See detailpH Dependence of the morphology of aqueous micelles formed by polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) copolymers
Gohy, Jean-François; Willet, Nicolas ULg; Varshney, Sunil K et al

in e-Polymers (2002), (35), 1-10

The morphology of micelles formed by two polystyrene-block-poly(2-vinylpyridine)- block-poly(ethylene oxide) (PS-b-P2VP-b-PEO) copolymers was studied in water by dynamic light scattering and transmission ... [more ▼]

The morphology of micelles formed by two polystyrene-block-poly(2-vinylpyridine)- block-poly(ethylene oxide) (PS-b-P2VP-b-PEO) copolymers was studied in water by dynamic light scattering and transmission electron microscopy. Spherical micelles were observed that consist of a PS core, a P2VP shell and a PEO corona. The characteristic size of core, shell and corona depends on the copolymer composition. An important increase in micellar size occurs at pH < 5 as a result of P2VP block protonation. The reversibility of this pH effect depends on copolymer composition, too. The conformation of the PEO block plays an important role in this pH driven morphological transition. [less ▲]

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See detailNovel unsaturated epsilon-caprolactone polymerizable by ring-opening and ring-opening metathesis mechanisms
Lou, Xudong; Detrembleur, Christophe ULg; Lecomte, Philippe ULg et al

in e-Polymers (2002), (34), 1-12

Ring-opening polymerization (ROP) and ring-opening metathesis polymerization (ROMP) of an unsaturated epsilon-caprolactone, 6,7-dihydro-2(3H)-oxepinone (DHO2), are alternative routes to produce ... [more ▼]

Ring-opening polymerization (ROP) and ring-opening metathesis polymerization (ROMP) of an unsaturated epsilon-caprolactone, 6,7-dihydro-2(3H)-oxepinone (DHO2), are alternative routes to produce unsaturated aliphatic polyesters with the same molecular structure. Polymerization of DHO2 initiated by Al isopropoxide in toluene at room temperature or at 0°C proceeds by a coordination-insertion mechanism, although intramolecular transesterification takes place beyond complete monomer conversion. The molecular weight distribution is narrow as long as monomer conversion does not exceed 90%. Ring-opening metathesis polymerization of DHO2 initiated by Schrock's Mo-based catalyst, 1, at 60°C allows higher molecular weight unsaturated polyester to be prepared, even though an intramolecular side reaction also operates. The structure of poly(DHO2) synthesized by ROP and ROMP is the same, as confirmed by 1H, 13C NMR, and FT-IR spectra. Copolymers of DHO2 with norbornene, cis-cyclooctene, and 1,5-cyclooctadiene have been successfully prepared. [less ▲]

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See detailpH-Dependence of the morphology of micelles formed by poly(2-vinylpyridine)-block-poly(ethylene oxide) copolymers in water
Gohy, Jean-François; Mores, Sandrine; Varshney, Sunil K et al

in e-Polymers (2002), (21), 1-8

The morphology of micelles formed by two poly(2-vinylpyridine)-block-poly(ethylene oxide) (P2VP-b-PEO) copolymers has been studied in phosphate-buffered water by dynamic light scattering and transmission ... [more ▼]

The morphology of micelles formed by two poly(2-vinylpyridine)-block-poly(ethylene oxide) (P2VP-b-PEO) copolymers has been studied in phosphate-buffered water by dynamic light scattering and transmission electron microscopy. Spherical micelles are observed when the P2VP block is the minor component of the diblock copolymer. When P2VP dominates the composition, transition from spheres-to-rods-to-vesicles takes place in a narrow pH range that straddles the pKa of P2VP. This transition is controlled by the degree of protonation of the P2VP blocks. At high pH, the copolymer precipitates from the solution. [less ▲]

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See detailSodium nitrite and ascorbic acid: a metal-free combination that controls the free-radical polymerization of tert-butyl methacrylate in water
Detrembleur, Christophe ULg; Mouithys-Mickalad, Ange ULg; Teyssié, Philippe et al

in e-Polymers (2002), (4), 1-16

A mixture of sodium nitrite and ascorbic acid is able to control the radical polymerization of tert-butyl methacrylate (tBMA) in water at 80°C. Indeed, sodium nitrite is reduced by the ascorbic acid, and ... [more ▼]

A mixture of sodium nitrite and ascorbic acid is able to control the radical polymerization of tert-butyl methacrylate (tBMA) in water at 80°C. Indeed, sodium nitrite is reduced by the ascorbic acid, and the nitric oxide (NO) which is formed in situ is nothing but a promoter of nitroxyl radicals. The radical polymerization of tBMA is thus basically controlled by a nitroxide-mediated process. [less ▲]

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See detailKey criteria for the design of polymeric stabilizers for aqueous titanium dioxide dispersions of high solid content
Creutz, Serge; Jérôme, Robert ULg

in e-Polymers (2001), (14), 1-9

Amphiphilic copolymers consisting of an animated hydrophobic block and a hydrophilic poly(sodium methacrylate) one have been synthesized with different structures and tested as stabilizers for aqueous ... [more ▼]

Amphiphilic copolymers consisting of an animated hydrophobic block and a hydrophilic poly(sodium methacrylate) one have been synthesized with different structures and tested as stabilizers for aqueous dispersions of alumina coated titanium dioxide (80 wt.-% solid). The dispersion stability is ruled by the strength of the anchoring of the aminated block onto the pigment and by the dynamics of the micelles formed by the copolymer. Any decrease in the anchoring strength, for example as a result of higher steric hindrance for the adsorbing block or of random rather than blocky distribution of the aminated co-units, is detrimental to the dispersion stability and makes this stability more dependent on the copolymer composition. Indeed, the position and dynamics of the unimers micelles equilibrium then control the adsorption of the copolymer on the pigment during the grinding process. [less ▲]

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See detailPoly(e-caprolactone) layered silicate nanocomposites: effect of clay surface modifiers on the melt intercalation process
Pantoustier, Nadège; Alexandre, Michaël ULg; Degée, Philippe et al

in e-Polymers (2001), (9), 1-9

Nanocomposites based on biodegradable poly(e-caprolactone) (PCL) and layered silicates (montmorillonite) modified by various alkylammonium cations were prepared by melt intercalation. Depending on whether ... [more ▼]

Nanocomposites based on biodegradable poly(e-caprolactone) (PCL) and layered silicates (montmorillonite) modified by various alkylammonium cations were prepared by melt intercalation. Depending on whether the ammonium cations contain non-functional alkyl chains or chains terminated by carboxylic acid or hydroxyl functions, microcomposites or nanocomposites were recovered as shown by X-ray diffraction and transmission electron microscopy. Mechanical and thermal properties were examined by tensile testing and thermogravimetric analysis. The layered silicate PCL nanocomposites exhibited some improvement of the mechanical properties (higher Young's modulus) and increased thermal stability as well as enhanced flame retardant characteristics as result of a charring effect. This communication aims at reporting that the formation of PCL-based nanocomposites strictly depends on the nature of the ammonium cation and its functionality, but also on the selected synthetic route, i.e. melt intercalation vs. in situ intercalative polymerization. Typically, protonated w-aminododecanoic acid exchanged montmorillonite allowed to intercalate e-caprolactone monomer and yielded nanocomposites upon in situ polymerization, whereas they exclusively formed microcomposites when blended with preformed PCL chains. In other words, it is shown that the formation of polymer layered silicate nanocomposites is not straightforward and cannot be predicted since it strongly depends on parameters such as ammonium cation type and functionality together with the production procedure, i.e., melt intercalation, solvent evaporation or in situ polymerization [less ▲]

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