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See detailControlled ring-opening polymerization of epsilon-caprolactone in the presence of layered silicates and formation of nanocomposites
Kubies, Dana; Pantoustier, Nadège; Dubois, Philippe et al

in Macromolecules (2002), 35

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See detailControlled ring-opening polymerization of epsilon-caprolactone promoted by "in situ" formed yttrium alkoxides
Martin, Eric; Dubois, Philippe ULg; Jérôme, Robert ULg

in Macromolecules (2000), 33(5), 1530-1535

The ring-opening polymerization of ε-caprolactone has been initiated by [tris(hexamethyldisilyl)amide]yttrium in the presence of an excess of 2-propanol. This initiating system is very active even at high ... [more ▼]

The ring-opening polymerization of ε-caprolactone has been initiated by [tris(hexamethyldisilyl)amide]yttrium in the presence of an excess of 2-propanol. This initiating system is very active even at high alcohol-to-Y molar ratio. Polymers with controlled molecular parameters (Mn, end groups) and low dispersity are formed as result of fast alkoxide/alcohol exchange. At molar excess of 2-propanol higher than 100, this exchange is no longer quantitative. The in situ formed active species involved in this new initiating system are different from those ones present in the commercial yttrium oxo-isopropoxide Y5(μ-O)(OiPr)13 cluster. Evidence is provided by 1H NMR spectroscopy. [less ▲]

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See detailControlled substances and other source gases, Chapter 1 of the Scientific Assessment of Ozone Depletion: 2002
Montzka, S. A.; Fraser, P. J.; Butler, J. H. et al

in Nohende Ajavon, Ayité-Lô; Albritton, Daniel L.; Mégie, Gérard (Eds.) et al Scientific Assessment of Ozone Depletion: 2002 (2003)

This chapter provides an update on scientific progress since the previous Scientific Assessment of Ozone Depletion (WMO, 1999) regarding ozone-depleting substances (ODSs) in the atmosphere. This includes ... [more ▼]

This chapter provides an update on scientific progress since the previous Scientific Assessment of Ozone Depletion (WMO, 1999) regarding ozone-depleting substances (ODSs) in the atmosphere. This includes a discussion of the latest available data for observed trends in the troposphere and stratosphere, emissions, lifetimes, Ozone Depletion Potentials (ODPs), and Global Warming Potentials (GWPs). On the basis of this updated informaion, we relate observations of ODSs in the atmosphere to expectations, and discuss the evidence that the Montreal Protocol is effectively reducing ozone-depleting gases in the atmosphere. [less ▲]

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See detailControlled synthesis and chemical modification of unsaturated aliphatic (co)polyesters based on 6,7-dihydro-2(3H)-oxepinone
Lou, Xudong; Detrembleur, Christophe ULg; Lecomte, Philippe ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2002), 40(14), 2286-2297

A pure unsaturated cyclic ester, 6,7-dihydro-2(3H)-oxepinone (DHO2), was prepared by a new synthetic route. The copolymerization of DHO2 with epsilon-caprolactone (CL) was initiated by aluminum ... [more ▼]

A pure unsaturated cyclic ester, 6,7-dihydro-2(3H)-oxepinone (DHO2), was prepared by a new synthetic route. The copolymerization of DHO2 with epsilon-caprolactone (CL) was initiated by aluminum isopropoxide [Al(OiPr)3] at 0 °C as an easy way to produce unsaturated aliphatic polyesters with nonconjugated CC double bonds in a controlled manner. The chain growth was living, as certified by the agreement between the experimental molecular weight at total monomer conversion and the value predicted from the initial monomer/initiator molar ratio. The polydispersity was reasonably low (weight-average molecular weight/number-average molecular weight 1.2). The homopolymerization of DHO2 was, however, not controlled because of fast intramolecular transesterification. Copolymers of DHO2 and CL were quantitatively oxidized with the formation of epoxides containing chains. The extent of the epoxidation allowed the thermal properties and thermal stability of the copolyesters to be modulated. The epoxidized copolyesters were successfully converted into thioaminated chains, which were then quaternized into polycations. No degradation occurred during the chemical modification. [less ▲]

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See detailControlled synthesis and interface properties of new amphiphilic PCL-g-PEO copolymers
Rieger, Jutta ULg; Dubois, Philippe ULg; Jérôme, Robert ULg et al

in Langmuir (2006), 22(18), 7471-7479

Novel biodegradable and biocompatible poly(epsilon-caprolactone)-graft-poly(ethylene oxide), PCL-g-PEO, copolymers consisting of biocompatible blocks have been synthesized by ring-opening copolymerization ... [more ▼]

Novel biodegradable and biocompatible poly(epsilon-caprolactone)-graft-poly(ethylene oxide), PCL-g-PEO, copolymers consisting of biocompatible blocks have been synthesized by ring-opening copolymerization of epsilon-caprolactone (epsilon CL) and a poly(ethylene oxide) (PEO) macromonomer, i.e., PEO end-capped by an epsilon-caprolactone unit (gamma PEO.CL). The control is effective on the composition and length of both the hydrophobic polyester backbone and the hydrophilic PEO grafts. The reactivity ratios have been determined by monitoring the copolymer composition in relation to the comonomer conversion. The PCL-g-PEO copolymers have a tapered (gradient) rather than a random structure consistent with r(epsilon)CL = 3.95 and r(gamma)PEO.CL = 0.05. The amphiphilic graft copolymers display surfactant properties similar to those of PEO-b-PCL diblock copolymers of comparable composition and solubility, as supported by CHCl3/water interfacial tension measured by the pendant drop method. [less ▲]

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See detailControlled Synthesis of AB2 amphiphilic triarm star-shaped block copolymers by ring-opening polymerization
Petrova, Svetla; Riva, Raphaël ULg; Jérôme, Christine ULg et al

in European Polymer Journal (2009), 45(12), 3442-3450

This paper describes the synthesis of a novel amphiphilic AB2 triarm star-shaped copolymer with A = non-toxic and biocompatible hydrophilic poly(ethylene oxide) (PEO) and B = biodegradable and hydrophobic ... [more ▼]

This paper describes the synthesis of a novel amphiphilic AB2 triarm star-shaped copolymer with A = non-toxic and biocompatible hydrophilic poly(ethylene oxide) (PEO) and B = biodegradable and hydrophobic poly(ε-caprolactone) (PCL). A series of AB2 triarm star-shaped copolymers with different molecular weights for the PCL block were successfully synthesized by a three-step procedure. α-methoxy-ω-epoxy-poly(ethylene oxide) (PEO-epoxide) was first synthesized by the nucleophilic substitution of α-methoxy-ω-hydroxy-poly(ethylene oxide) (MPEO) on epichlorohydrin. In a second step, the α-methoxy-ω,ω’-dihydroxy-poly(ethylene oxide) (PEO(OH)2) macroinitiator was prepared by the selective hydrolysis of the ω-epoxy end-group of the PEO-epoxide chain. Finally, PEO(OH)2 was used as a macroinitiator for the ring-opening polymerization (ROP) of ε-caprolactone (εCL) catalyzed by tin octoaote (Sn(Oct)2). PEO-epoxide, PEO(OH)2 and the AB2 triarm star-shaped copolymers were assessed by 1H NMR spectroscopy, size exclusion chromatography (SEC) and MALDI-TOF. The behavior of the AB2 triarm star-shaped copolymer in aqueous solution was studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). [less ▲]

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See detailControlled synthesis of an ABC miktoarm star-shaped copolymer by sequential ring-opening polymerization of ethylene oxide, benzyl beta-malolactonate, and epsilon-caprolactone
Rieger, Jutta ULg; Coulembier, Olivier; Dubois, Philippe ULg et al

in Macromolecules (2005), 38(26), 10650-10657

This paper reports on the synthesis of an amphiphilic miktoarm ABC star-shaped copolymer, s[(PEO)(PMLABz)(PCL)], consisting of biocompatible/bioresorbable arms. Indeed, PEO is a hydrophilic biocompatible ... [more ▼]

This paper reports on the synthesis of an amphiphilic miktoarm ABC star-shaped copolymer, s[(PEO)(PMLABz)(PCL)], consisting of biocompatible/bioresorbable arms. Indeed, PEO is a hydrophilic biocompatible poly(ethylene oxide) arm, PMLABz is a poly(benzyl beta-malolactonate) arm precursor of a pH-sensitive bioresorbable poly(beta-malic acid) block, and PCL is a hydrophobic bioresorbable poly(epsilon-caprolactone) arm. Each constitutive arm was prepared by ring-opening polymerization. A double-headed PEO macroinitiator [PEO-(OH)-COO-K+] was first prepared by selective hydrolysis of the alpha-lactone (2-oxepanone) end group of PEO chains end-capped by a omega-methoxy group. The anionic polymerization of benzyl beta-malolactonate (MLABz) was selectively initiated by the alpha-potassium carboxylate end group of PEO in the presence of 18-crown-6 ether. The polymerization of epsilon-caprolactone (epsilon-CL) was initiated by the hydroxyl group left at the junction of the two blocks of the as-prepared PEO-b-PMLABz diblock copolymer, in the presence of tin(II) bis(2-ethylhexanoate) (Sn(Oct)(2)). The macroinitiator, the intermediate diblock, and the final miktoarm. star-shaped copolymer were analyzed by H-1 NMR spectroscopy and size exclusion chromatography. [less ▲]

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See detailControlled synthesis of anthracene-labeled omega-amine polystyrene to be used as a probe for interfacial reaction with mutually reactive PMMA
Yin, Zhihui; Koulic, Christian; Pagnoulle, Christophe et al

in Macromolecular Chemistry and Physics (2002), 203(14), 2021-2028

Anthracene-labeled polystyrene (PS) end-capped by a primary amine has been synthesized by atom transfer radical copolymerization of styrene with 3-isopropenyl-alpha,alpha-dimethylbenzyl isocyanate (m-TMI ... [more ▼]

Anthracene-labeled polystyrene (PS) end-capped by a primary amine has been synthesized by atom transfer radical copolymerization of styrene with 3-isopropenyl-alpha,alpha-dimethylbenzyl isocyanate (m-TMI). The m-TMI co-monomer (5.7 mol-%) does not perturb the control of the radical polymerization of styrene. The pendant isocyanate groups of the copolymer chains of low polydispersity (M-w/M-n = 1.25) and controlled molecular weight (up to 35 000) have been derivatized into anthracene by a reaction with 9-methyl(aminomethyl)anthracene. The anthracene-labeled PS (ca. 2 mol-% label) has been conveniently analyzed by size-exclusion chromatography with a UV detector (SEC-UV). Moreover, the omega-bromide end-group of the copolymer chains has been derivatized into a primary amine, making the labeled PS chains reactive towards non-miscible poly(methyl methacrylate) (PMMA) chains end-capped by an anhydride. The interfacial coupling of the mutually reactive PS and PMMA chains has been studied under static conditions (i.e., at the interface between thin PS and PMMA films) and successfully analyzed by SEC-UV. [less ▲]

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See detailControlled synthesis of carboxylic acid end-capped poly(heptadecafluorodecyl acrylate) and copolymers with 2-hydroxyethyl acrylate
Grignard, Bruno ULg; Jérôme, Christine ULg; Calberg, Cédric ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2007), 45(8), 1499-1506

1H,1H,2H,2H-Heptadecafluorodecyl acrylate (AC8) was polymerized by reversible addition-fragmentation chain transfer and copolymerized with 2-hydroxyethyl acrylate with the formation of random and block ... [more ▼]

1H,1H,2H,2H-Heptadecafluorodecyl acrylate (AC8) was polymerized by reversible addition-fragmentation chain transfer and copolymerized with 2-hydroxyethyl acrylate with the formation of random and block copolymers, respectively. The kinetics of the (co)polymerization was monitored with H-1 NMR spectroscopy and showed that the homopolymerization and random copolymerization of AC8 were under control. As a result of this control and the use of S-1-dodecyl-S-(alpha,alpha'-dimethyl-alpha"-acetic acid)trithiocarbonate as a chain-transfer agent, the copolymer chains were end-capped by an a-carboxylic acid group. Moreover, the controlled polymerization of AC8 was confirmed by the successful synthesis of poly(1H,1H,2H,2H-heptadecafluorodecyl acrylate)-b-poly(2hydroxyethyl acrylate) diblock copolymers, which were typically amphiphilic compounds. [less ▲]

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See detailControlled synthesis of ethylene-vinyl acetate based copolymers by organometallic mediated radical polymerization
Demarteau, Jérémy ULg; Kermagoret, Anthony ULg; Jérôme, Christine ULg et al

in Matyjaszewski, Krzysztof; Sumerlin, Brent S.; Tsarevsky, Nicolay V. (Eds.) et al Controlled Radical Polymerization: Materials (2015)

The controlled radical copolymerization of ethylene (E) and vinyl acetate (VAc) is further investigated by organometallic- mediated radical polymerization (OMRP) using Co(acac)2 as controlling agent at ... [more ▼]

The controlled radical copolymerization of ethylene (E) and vinyl acetate (VAc) is further investigated by organometallic- mediated radical polymerization (OMRP) using Co(acac)2 as controlling agent at ethylene pressure up to 100 bar. The effect of ethylene pressure on kinetics, level of control and copolymer composition, is discussed. Ethylene-Vinyl Acetate copolymers (EVAs) with low dispersities and ethylene content reaching 57 mol% are notably reported. This work also successfully addresses the precision design of EVA-containing block copolymers, i.e. PVAc-block-EVA. In this case, the order of the synthesis of the blocks is a key parameter. The “PVAc-first” strategy is by far more practical and efficient. [less ▲]

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See detailControlled synthesis of multi-functional polymers bearing pendant catechols for surface modifications
Patil, Nagaraj ULg; Aqil, Abdelhafid ULg; Jérôme, Christine ULg et al

Poster (2015, June)

Poly(ethylene glycol) (PEG)-based polymers have been widely employed in anti-fouling coating applications due to their robust bio-relevant properties including water solubility and biocompatibility ... [more ▼]

Poly(ethylene glycol) (PEG)-based polymers have been widely employed in anti-fouling coating applications due to their robust bio-relevant properties including water solubility and biocompatibility. However, limited by its poor adhesion towards surfaces, demands an addition modification strategies. Mussel adhesive proteins (MAPs) are potential models for adhesive polymers, which exhibits underwater adhesion towards dissimilar materials under environmentally challenging conditions. Most often experimentally simple, but structurally complex poly(dopamine) has been used as an analogues of MAPs for metal chelation, cross-linking and surface binding purposes. Inspired by MAPs, we have developed catechol-bearing copolymers for surface adhesion of stainless steel. This study describes the synthesis and reversible addition−fragmentation chain transfer (RAFT) polymerization of mussel-inspired acetonide-protected dopamine (meth)acrylamide monomers (ADA and ADMA). A series of well-defined P(PEGAm-b-ADAn) and P(ADMAn-b-PEGMAm) copolymers across a range of molar masses (13−42 kg/mol) with low molar mass dispersities (Đ = 1.12−1.25) were reported for the first time. Post polymerization TFA treatment yields block copolymers bearing free –catechol units in quantitative yields (>95%). The self-assembling nature of amphiphilic block-copolymers was studied by 1H-NMR, DLS and TEM. Surface functionalization and anti-fouling experiments were performed in real time using quartz crystal microbalance coupled with dissipation (QCM-D). The copolymer upon oxidation yields reactive quinones, which can be exploited to cross-link with chitosan (also, polymers with free –NH2 and –SH groups), thereby producing nano(macro)gels. In general, these novel class of block copolymeric ligand systems can be foreseen as versatile ingredients in material chemistry to obtain biocompatible multifunctional systems, benefited by high water solubility with inherent stealth ability and protein-repellency, as well as effective chelating groups, and may find application for a variety of biomedical fields, of which we have illustrated an important example. [less ▲]

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See detailControlled synthesis of poly(vinylamine)-based copolymers by organometallic-mediated radical polymerization
Dréan, Mathilde ULg; Guégan, Philippe; Detrembleur, Christophe ULg et al

in Macromolecules (2016), 49(13), 4817-4827

iving/controlled polymerization methods have enabled the synthesis of numerous (co)polymers with defined compositions and architectures. However, the precision design of poly(vinylamine)-based copolymers ... [more ▼]

iving/controlled polymerization methods have enabled the synthesis of numerous (co)polymers with defined compositions and architectures. However, the precision design of poly(vinylamine)-based copolymers remains challenging despite their extensive use in various fields of applications and the clear benefits to finely tune their properties. Here, we report on a two-step strategy for the synthesis of tailor-made poly(vinylamine) derivatives through the organometallic- mediated radical (co)polymerization (OMRP) of N-vinyl- acetamide and/or N-methylvinylacetamide followed by acid hydrolysis of the acetamide groups. A series of well-defined homopolymers as well as statistical and block copolymers with pendant primary and/or secondary amines having controlled molar masses, compositions, and low dispersities were produced accordingly. The reactivity ratios of the comonomers as well as the composition drift along the chain were determined in order to have a precise idea of the polymer structures. These advances represent a significant step toward an efficient platform for synthesis of this important class of amino group-containing (co)polymers. [less ▲]

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See detailControlled synthesis of unsaturated aliphatic polyesters
Lou, Xudong; Detrembleur, Christophe ULg; Jérôme, Robert ULg

Poster (2003, May 16)

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See detailControlled whole body vibration to decrease fall risk and improve health related quality of life in elderly patients
Bruyère, Olivier ULg; Wuidart, M. A.; di Palma, E. et al

in Osteoporosis International (2003, November), 14(Suppl. 7), 63

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See detailControlled whole body vibration to decrease fall risk and improve health-related quality of life of nursing home residents
Bruyère, Olivier ULg; Wuidart, M. A.; Di Palma, E. et al

in Archives of Physical Medicine & Rehabilitation (2005), 86(2), 303-307

Objective: To investigate the effects of whole body vibration in the elderly. Design: Randomized controlled trial. Setting: Nursing home. Participants: Forty-two elderly volunteers. Interventions: Six ... [more ▼]

Objective: To investigate the effects of whole body vibration in the elderly. Design: Randomized controlled trial. Setting: Nursing home. Participants: Forty-two elderly volunteers. Interventions: Six-week vibration intervention plus physical therapy (PT) (n=22) or PT alone (n=20). Main Outcome Measures: We assessed gait and body balance using the Tinetti test (maximum scores of 12 for gait, 16 for body balance, 28 for global score), motor capacity using the Timed Up & Go (TUG) test, and health-related quality of life (HRQOL) using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Results: After 6 weeks, the vibration intervention group improved by a mean +/- standard deviation of 2.4 +/- 2.3 points on the gait score compared with no score change in the control group (P<.001). The intervention group improved by 3.5 +/- 2.1 points on the body balance score compared with a decrease of 03 +/- 1.2 points in the control group (P<.001). TUG test time decreased by 11.0 +/- 8.6 seconds in the treated group compared with an increase of 2.6 +/- 8.8 seconds in the control group (P<.001). The intervention group had significantly greater improvements from baseline on 8 of 9 items on the SF-36 compared with the control group. Conclusions: Controlled whole body vibration can improve elements of fall risk and HRQOL in elderly patients. [less ▲]

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See detailControlled whole body vibrations improve health related quality of life in elderly patients
Bruyère, Olivier ULg; Wuidart, Marc-Antoine; Di Palma, Elio et al

in Arthritis and Rheumatism (2003, September), 48(9, Suppl. S), 502

Detailed reference viewed: 101 (9 ULg)