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See detailLes pollutions dans l'air intérieur des bâtiments - Diagnostic - Incidences sur la santé.
Kuske, Martyna; Nicolas, Jacques ULg

Book published by FUL et Observatoire de la santé (2000)

Ce n’est qu’au cours des années 70 que certains problèmes de santé ont pu être directement associés à l’environnement intérieur des maisons. Les crises pétrolières ont stimulé une réduction de la ... [more ▼]

Ce n’est qu’au cours des années 70 que certains problèmes de santé ont pu être directement associés à l’environnement intérieur des maisons. Les crises pétrolières ont stimulé une réduction de la consommation d’énergie, entraînant le renforcement de l'isolation thermique des maisons et une réduction de leur ventilation. Si l'objectif énergétique est atteint, il faut constater à présent que la plupart de ces actions ont provoqué l'augmentation des concentrations de certains polluants à l’intérieur des maisons. Cette problématique, généralement connue sous l'appellation "Indoor Pollution", a fait l'objet de nombreuses études et publications. Mais pour améliorer la situation, il ne suffit pas d'inventorier, voire d'étudier les effets possibles des polluants sur la santé, encore faut-il prendre les mesures nécessaires pour remédier au problème. Le présent ouvrage tente de couvrir l'ensemble de la question. Il constitue le résultat d'une recherche bibliographique de publications européennes et mondiales traitant du sujet, de travaux de chercheurs et d’étudiants de la F.U.L., de contacts avec les institutions et organisations s'occupant de la pollution intérieure ainsi que d’expériences personnelles dans ce domaine. Il est le fruit d'une réflexion commune entre la Province de Luxembourg et la F.U.L., dans l'esprit de la mise en place de services d'intervention en matière de pollution intérieure. Il s'adresse donc essentiellement à tous les professionnels qui, de près ou de loin, sont concernés par la question. En une bonne centaine de pages, le livre reprend synthétiquement chacun des principaux polluants communément rencontrés dans les maisons, et plus particulièrement en Belgique. Il en identifie les sources et les effets sur la santé, ainsi que la réglementation les concernant et un certain nombre de conseils pratiques. Par rapport à l'information généralement disponible dans d'autres ouvrages, celui-ci ajoute les méthodes d’analyses de référence ainsi que les techniques alternatives de détection de chaque polluant. Un accent tout particulier à été mis sur les méthodes optimales de terrain à mettre en place par un service de conseil d’analyse de l’air dans les bâtiments. Cette publication, originale par son caractère pratique et complet, doit intéresser un grand nombre de personnes concernées par la problématique de la pollution intérieure : les scientifiques, les médecins, les laboratoires, les pouvoirs publics, et en particulier les responsables et les travailleurs des services d’intervention en matière de pollutions intérieures, les services de sécurité et d’hygiène, etc. [less ▲]

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See detailPoly (D,L-lactic acid) macroporous guidance scaffolds seeded with Schwann cells genetically modified to secrete bi-functional neurotrophin implanted in the completely transected adult rat thoracic spinal cord
Hurtado, Andres; Moon, Lawrence D F; Maquet, Véronique et al

in Biomaterials (2006), 27(3), 430-442

Freeze-dried poly(D,L-lactic acid) macroporous scaffold filled with a fibrin solution containing Schwann cells (SCs) lentivirally transduced to produce and secrete D15A, a bi-functional neurotrophin with ... [more ▼]

Freeze-dried poly(D,L-lactic acid) macroporous scaffold filled with a fibrin solution containing Schwann cells (SCs) lentivirally transduced to produce and secrete D15A, a bi-functional neurotrophin with brain-derived neurotrophic factor and neurotrophin-3 activity, and to express green fluorescent protein (GFP) were implanted in the completely transected adult rat thoracic spinal cord. Control rats were similarly injured and then implanted with scaffolds containing the fibrin solution with SCs lentivirally transduced to produce express GFP only or with the fibrin solution only. Transgene production and biological activity in vitro, SC survival within the scaffold in vitro and in vivo, scaffold integration, axonal regeneration and myelination, and hind limb motor function were analyzed at 1, 2, and 6 weeks after implantation. In vitro, lentivirally transduced SCs produced 87.5 ng/24 h/10(6) Cells of D15A as measured by neurotrophin-3 activity in ELISA. The secreted D15A was biologically active as evidenced by its promotion of neurite outgrowth of dorsal root ganglion neurons in culture. In vitro, SCs expressing GFP were present in the scaffolds for up to 6 It, the end of a typical surgery session. Implantation of SC-seeded scaffolds caused modest loss of spinal nervous tissue. Reactive astrocytes and chondroitin sulfate glycosaminoglycans were present in spinal tissue adjacent to the scaffold. Vascularization of the scaffold was ongoing at I week post-implantation. There were no apparent differences in scaffold integration and blood vessel formation between groups. A decreasing number of implanted (GFP-positive) SCs were found within the scaffold during the first 3 days after implantation. Apoptosis was identified as one of the mechanisms of cell death. At 1 week and later time points after implantation, few of the implanted SCs were present in the scaffold. Neurofilament-positive axons were found in the scaffold. At 6 weeks post-grafting, myelinated axons were observed within and at the external surface of the scaffold. Axons did not grow from the scaffold into the caudal cord. All groups demonstrated a similar improvement of hind limb motor function. Our findings demonstrated that few seeded SCs survived in vivo, which could account for the modest axonal regeneration response into and across the scaffold. For the development of SC-seeded macroporous scaffolds that effectively promote axonal regeneration in the injured spinal cord, the survival and/or total number of SCs in the scaffold needs to be improved. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailPoly (ε-caprolactone-b-glycolide) and Poly(D,L-lactide-b-glycolide) diblock copolyesters: controlled synthesis, characterization, and colloidal dispersions
Barakat, Ibrahim; Dubois, Philippe ULg; Grandfils, Christian ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2001), 39(2), 294-306

Living -aluminum alkoxide poly--caprolactone and poly-D,L-lactide chains were synthesized by the ring-opening polymerization of -caprolactone (-CL) and D,L-lactide (D,L-LA), respectively, and were used as ... [more ▼]

Living -aluminum alkoxide poly--caprolactone and poly-D,L-lactide chains were synthesized by the ring-opening polymerization of -caprolactone (-CL) and D,L-lactide (D,L-LA), respectively, and were used as macroinitiators for glycolide (GA) polymerization in tetrahydrofuran at 40 °C. The P(CL-b-GA) and P(LA-b-GA) diblock copolymers that formed were fractionated by the use of a selective solvent for each block and were characterized by 1H NMR spectroscopy and differential scanning calorimetry analysis. The livingness of the operative coordination-insertion mechanism is responsible for the control of the copolyester composition, the length of the blocks, and, ultimately, the thermal behavior. Because of the inherent insolubility of the polyglycolide blocks, microphase separation occurs during the course of the sequential polymerization, resulting in a stable, colloidal, nonaqueous copolymer dispersion, as confirmed by photon correlation spectroscopy. [less ▲]

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See detailPoly [glycidyl methacrylate (GMA) / methylmethacrylate (MMA)-b-butadiene (B)-b-GMA/MMA] reactive thermoplastic elastomers: synthesis and characterization
Yu, Jian Ming; Dubois, Philippe ULg; Jérôme, Robert ULg

in Journal of Polymer Science. Part A, Polymer Chemistry (1997), 35(16), 3507-3515

New block copolymers of the ABA type, where B stands for polybutadiene (PBD) and A for polyglycidylmethacrylate(PGMA), poly(methylmethacrylate(MMA)-co-GMA) and PMMA-b-PGMA, respectively, have been ... [more ▼]

New block copolymers of the ABA type, where B stands for polybutadiene (PBD) and A for polyglycidylmethacrylate(PGMA), poly(methylmethacrylate(MMA)-co-GMA) and PMMA-b-PGMA, respectively, have been successfully synthesized by using the diadduct of tert-butyllithium (tert-BuLi) to meta-diisopropenylbenzene (m-DIB) as a difunctional initiator. The PBD midblock has been synthesized in a cyclohexane/diethylether (100/6, v/v) mixture at room temperature, whereas the methacrylate outer blocks have been synthesized in a cyclohexane/diethylether/THF (100/6/150, v/v/v) mixture at -78°C. Block copolymers of a very narrow molecular weight distribution (1.10) have been analyzed by differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and tensile testing. These materials are phase separated and can exhibit tensile strength up to 22 MPa together with very high elongation at break (1500%). [less ▲]

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See detailPoly(2-dimethylamino ethylmethacrylate)-Based Polymers To Camouflage Red Blood Cell Antigens
Cerda Cristerna, Bernardino Isaac ULg; COTTIN, Sophie ULg; Flebus, Luca ULg et al

in Biomacromolecules (2012), 13(4), 1172-1180

Poly(2-dimethylamino-ethylmethacrylate) (PDMAEMA) is a cationic polymer when dissolved in a 7.4 pH fluid. Owing to its ionic nature, this polycation interacts with the negatively charged cell membrane ... [more ▼]

Poly(2-dimethylamino-ethylmethacrylate) (PDMAEMA) is a cationic polymer when dissolved in a 7.4 pH fluid. Owing to its ionic nature, this polycation interacts with the negatively charged cell membrane surface of red blood cells (RBCs). The electrostatic self-assembly of PDMAEMA on RBCs membrane can be employed for inducing the formation of a polymeric shield camouflaging blood group antigens on RBCs as a valuable strategy for developing “universal RBCs” for blood transfusion. The purpose of this research was to evaluate the camouflaging ability of PDMAEMA homopolymers and PDMAEMA-copoly(nethylene glycol) copolymers differing in molecular weight and architecture. Surprisingly, the PDMAEMAs caused a partially masking, no masking, and sensitization of the same RBCs population. The MW and architecture of the polymers as well as temperature of PDMAEMA-RBCs treatment influenced the results observed. Herein, the very particular reactivity of PDMAEMAs and RBCs is analyzed and discussed. [less ▲]

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See detailPoly(2-oxepane-1,5-dione) : a highly crystalline modified poly (epsilon-caprolactone) of a high melting temperature
Tian, Dong; Halleux, Olivier; Dubois, Philippe ULg et al

in Macromolecules (1998), 31(3), 924-927

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See detailPoly(3-hydroxybutyrate) production by Cupriavidus necator using waste glycerol
Cavalheiro, Joao M.B.T.; de Almeida, M. Catarina M.D.; Grandfils, Christian ULg et al

in Process Biochemistry (2009), 44

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See detailPoly(A) RNA is reduced by half during bovine oocyte maturation but increases when meiotic arrest is maintained with CDK inhibitors.
Lequarré, Anne-Sophie ULg; Traverso, Juan M; Marchandise, Joelle et al

in Biology of Reproduction (2004), 71(2), 425-31

Variations in the amount of different RNA species were investigated during in vitro maturation of bovine oocytes. Total RNA content was estimated to be 2 ng before meiosis, and after meiosis resumption ... [more ▼]

Variations in the amount of different RNA species were investigated during in vitro maturation of bovine oocytes. Total RNA content was estimated to be 2 ng before meiosis, and after meiosis resumption, no decrease was observed. Ribosomal RNA did not appear to be degraded either, whereas poly(A) RNA was reduced by half after meiosis resumption, from 53 pg to 25 pg per oocyte. Real-time polymerase chain reaction was performed on growth and differentiation factor-9 (GDF-9), on cyclin B1, and on two genes implicated in the resistance to oxidative stress, glucose-6-phosphate-dehydrogenase (G6PD) and peroxiredoxin-6 (PRDX6). When these transcripts were reverse-transcribed with hexamers, the amplification results were not different before or after in vitro maturation. But when reverse transcription was performed with oligo(dT), amplification was dramatically reduced after maturation, except for cyclin B1 mRNA, implying deadenylation without degradation of three transcripts. Although calf oocytes have a lower developmental competence, their poly(A) RNA contents were not different from that of cow oocytes, nor were they differently affected during maturation. When bovine oocytes were maintained in vitro under meiotic arrest with CDK inhibitors, their poly(A) RNA amount increased, but this rise did not change the poly(A) RNA level once maturation was achieved. The increase could not be observed under transcription inhibition and, when impeding transcription and adenylation, the poly(A) RNA decreased to a level normally observed after maturation, in spite of the maintenance of meiotic arrest. These results demonstrate the importance of adenylation and deadenylation processes during in vitro maturation of bovine oocytes. [less ▲]

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See detailPoly(acrylic acid) with disulfide bond for the elaboration of pH-responsive brush surfaces
Van Camp, Wim; Du Prez, Filip E; Alem, Halima et al

in European Polymer Journal (2010), 46(2), 195-201

We report on a new route for the facile prepn. of pH-responsive tethered brushes on metallic surfaces, starting from poly(acrylic acid) (PAA) contg. a disulfide (S-S) bond (PAA-S-S-PAA). First, atom ... [more ▼]

We report on a new route for the facile prepn. of pH-responsive tethered brushes on metallic surfaces, starting from poly(acrylic acid) (PAA) contg. a disulfide (S-S) bond (PAA-S-S-PAA). First, atom transfer radical polymn. (ATRP) of 1-ethoxyethyl acrylate (EEA) with a disulfide-contg. initiator was performed to obtain the poly(EEA) precursor polymer (PEEA-S-S-PEEA). Deprotection of PEEA by a heating step resulted in the desired PAA chains without any further purifn. The brushes, obtained by the grafting to' of PAA-S-S-PAA onto gold, were then characterized by at. force microscopy in water at various pH values. The results evidence a large collapsing/swelling capacity. [less ▲]

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See detailPoly(acrylic acid)-block-poly(vinyl alcohol) anchored maghemite nanoparticles designed for multi-stimuli triggered drug release
Liu, Ji ULg; Detrembleur, Christophe ULg; Debuigne, Antoine ULg et al

in Nanoscale (2013), 5(23), 11464-11477

Original core/corona nanoparticles composed of amaghemite core and a stimuli-responsive polymer coating made of poly(acrylic acid)-block-poly(vinyl alcohol) macromolecules were fabricated for drug ... [more ▼]

Original core/corona nanoparticles composed of amaghemite core and a stimuli-responsive polymer coating made of poly(acrylic acid)-block-poly(vinyl alcohol) macromolecules were fabricated for drug delivery system (DDS) application. This kind of DDS aims to combine the advantage of stimuli-responsive polymer coating, in order to regulate the drug release behaviours under different conditions and furthermore, improve the biocompatibility and in vivo circulation half-time of the maghemite nanoparticles. Drug loading capacity was evaluated with methylene blue (MB), a cationic model drug. The triggered release of MB was studied under various stimuli such as pH, ionic strength and temperature. Local heating generated under alternating magnetic field (AMF) application was studied, and remotely AMF-triggered release was also confirmed, while a mild heating-up of the release medium was observed. Furthermore, their potential application as magnetic resonance imaging (MRI) contrast agents was explored via relaxivity measurements and acquisition of T2-weighted images. Preliminary studies on the cytotoxicity against mouse fibroblast-like L929 cell line and also their cellular uptake within human melanoma MEL-5 cell line were carried out. In conclusion, this kind of stimuli-responsive nanoparticles appears to be promising carriers for delivering drugs to some tumour sites or into cellular compartments with an acidic environment. [less ▲]

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See detailPoly(caprolactone)/clay masterbatches prepared in supercritical CO2 as efficient clay delamination promoters in poly(styrene-co-acrylonitrile)
Urbanczyk, Laetitia ULg; Calberg, Cédric ULg; Benali, Samira et al

in Journal of Materials Chemistry (2008), 18(39), 4623-4630

Poly(styrene-co-acrylonitrile) (SAN)/clay nanocomposites with a high degree of clay exfoliation were prepared upon melt blending of pre-exfoliated poly(-caprolactone) (PCL)/organoclay masterbatches in a ... [more ▼]

Poly(styrene-co-acrylonitrile) (SAN)/clay nanocomposites with a high degree of clay exfoliation were prepared upon melt blending of pre-exfoliated poly(-caprolactone) (PCL)/organoclay masterbatches in a Brabender-type internal mixer. These highly filled masterbatches were synthesized by a one-pot process using supercritical carbon dioxide as a polymerization medium. During their dispersion into SAN, PCL is expected to act as a compatibilizer at the polymer–clay interface as it is miscible with the host matrix under these conditions. Reference nanocomposites based on direct melt mixing of the commercial organoclay were also prepared for the sake of comparison. The superiority of the masterbatch route in term of clay delamination efficiency has been evidenced by XRD analysis, visual and TEM observations. The effect of the nanocomposite morphology on the polymer properties was then investigated. A substantial improvement of the fire behaviour and a decrease in gas permeability have been observed for the nanocomposite containing the highest level of clay exfoliation, accompanied with a higher brittleness as evidenced by traction and impact tests. [less ▲]

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See detailPoly(D,L-lactide) (PDLLA) foams with TiO2 nanoparticles and PDLLA/TiO2-Bioglass (R) foam composites for tissue engineering scaffolds
Boccaccini, Aldo R.; Blaker, Jonny J.; Maquet, Véronique et al

in Journal of Materials Science (2006), 41(13), 3999-4008

Porous poly(D,L-lactide) PDLLA foams containing 0, 5 and 20 wt% of TiO2 nanoparticles were fabricated and characterised. The addition of Bioglassg particles was also studied in a composite containing 5 wt ... [more ▼]

Porous poly(D,L-lactide) PDLLA foams containing 0, 5 and 20 wt% of TiO2 nanoparticles were fabricated and characterised. The addition of Bioglassg particles was also studied in a composite containing 5 wt% of Bioglass(R) particles and 20 wt% of TiO2 nanoparticles. The microstructure of the four different foam types was characterised using scanning electron microscopy (SEM) and their mechanical properties assessed by quasi-static compression testing. The in vitro behaviour of the foams was studied in simulated body fluid (SBF) at three different time points: 3, 21 and 28 days. The degradation of the samples was characterised quantitatively by measuring the water absorption and weight loss as a function of immersion time in SBE The bioactivity of the foams was characterised by observing hydroxyapatite (HA) formation after 21 days of immersion in SBF using SEM and confirmed with X-ray diffraction (XRD) analysis. It was found that the amount of HA was dependent on the distribution of TiO2 nanoparticles and on the presence of Bioglassg in the foam samples. (c) 2006 Springer Science + Business Media, Inc. [less ▲]

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See detailPoly(D,L-lactide) foams modified by poly(ethylene oxide)-block-poly(D,L-lactide) copolymers and a-FGF: in vitro and in vivo evaluation for spinal cord regeneration
Maquet, Véronique; Martin, Didier ULg; Scholtes, Félix ULg et al

in Biomaterials (2001), 22(10), 1137-1146

The first goal of this study was to examine the influence that poly(ethylene oxide)-block-poly(D,L-lactide) (PELA) copolymer can have on the wettability, the in vitro controlled delivery capability, and ... [more ▼]

The first goal of this study was to examine the influence that poly(ethylene oxide)-block-poly(D,L-lactide) (PELA) copolymer can have on the wettability, the in vitro controlled delivery capability, and the degradation of poly(D,L-lactide) (PDLLA) foams. These foams were prepared by freeze-drying and contain micropores (10 μm) in addition of macropores (100 μm) organized longitudinally. Weight loss, water absorption, changes in molecular weight, polymolecularity (Mw/Mn) and glass transition temperature ( Tg) of PDLLA foams mixed with various amounts of PELA were followed with time. It was found that 10 wt% of PELA increased the wettability and the degradation rate of the polymer foams. The release of sulforhodamine (SR) was compared for PDLLA and PDLLA-PELA foams in relation with the foam porosity. An initial burst release was observed only in the case of the 90:10 PDLLA/PELA foam. The ability of the foam of this composition to be integrated and to promote tissue repair and axonal regeneration in the transected rat spinal cord was investigated. After implantation of ca. 20 polymer rods assembled with fibrin-glue, the polymer construct was able to bridge the cord stumps by forming a permissive support for cellular migration, angiogenesis and axonal regrowth. [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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See detailPoly(epsilon-caprolactone)/clay nanocomposites by in-situ intercalative polymerization catalyzed by dibutyltin dimethoxide
Lepoittevin, Bénédicte; Pantoustier, Nadège; Devalckenaere, Myriam et al

in Macromolecules (2002), 35(22), 8385-8390

Poly(epsilon-caprolactone)/clay nanocomposites were prepared by in-situ ring-opening polymerization of epsilon-caprolactone by using dibutyltin dimethoxide as an initiator/catalyst. A nonmodified Na ... [more ▼]

Poly(epsilon-caprolactone)/clay nanocomposites were prepared by in-situ ring-opening polymerization of epsilon-caprolactone by using dibutyltin dimethoxide as an initiator/catalyst. A nonmodified Na+-montmorillonite and two montmorillonites surface-modified by dimethyl 2-ethylhexyl (hydrogenated tallow alkyl) and methyl bis(2-hydroxyethyl) (hydrogenated tallow alkyl) ammonium cations, respectively, were used. The evolution of molecular weights was followed in relation to silicate surface modification and clay concentration. The alcohol-bearing organo-modified clay was a co-initiator for the polymerization reaction and thus controlled the molecular weight of the PCL chains. Furthermore, the number-average molecular weight of the growing PCL chains linearly increased with the monomer conversion. Nanocomposites were analyzed by small-angle X-ray diffraction, transmission electron microscopy, and thermogravimetry. The clay dispersion depended on the structure of the alkylammonium used to make the clay more hydrophobic. Exfoliated nanocomposites were formed when hydroxyl-containing alkylammonium. was used; otherwise, intercalated structures were reported. Thermogravimetric analyses showed a higher degradation temperature for the exfoliated structures than for the intercalated ones, both of them exceeding the degradation temperature of unfilled poly(epsilon-caprolactone). [less ▲]

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See detailPoly(epsilon-caprolactone)/clay nanocomposites prepared by melt intercalation: mechanical, thermal and rheological properties
Lepoittevin, Bénédicte; Devalckenaere, Myriam; Pantoustier, Nadège et al

in Polymer (2002), 43(14), 4017-4023

(Nano)composites of poly(epsilon-caprolactone) (PCL) were prepared by melt blending the polymer with natural Na+ montmorillonite and montmorillonite modified by hydrogenated tallowalkyl (HTA)-based ... [more ▼]

(Nano)composites of poly(epsilon-caprolactone) (PCL) were prepared by melt blending the polymer with natural Na+ montmorillonite and montmorillonite modified by hydrogenated tallowalkyl (HTA)-based quaternary ammonium cations, such as dimethyl 2-ethylhexyl HTA ammonium and methyl bis(2-hydroxyethyl) HTA ammonium. Microcomposites or nanocomposites were prepared depending on whether neat or modified montmorillonites was used, as assessed by X-ray diffraction and transmission electron microscopy. Mechanical and thermal properties were studied as a function of the filter content by tensile testing, Izod impact testing, thermogravimetric analysis and differential scanning calorimetry. The rheological behaviour at 80 degreesC was also analysed in relation to the structure and content of the layered silicate. Effect of exfoliated silicates on the mechanical properties, thermal stability and flame resistance of PCL was considered. Stiffness and thermal stability improved with the filler loading until a content of 5 wt%. Further loading resulted in the levelling off and possibly in a decrease of these properties. A marked charring effect was observed upon exposure to a flame. [less ▲]

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See detailPoly(ethylene-co-vinyl acetate)/clay nanocomposites: Effect of clay nature and organic modifiers on morphology, mechanical and thermal properties
Peeterbroeck, Sophie; Alexandre, Michaël ULg; Jérôme, Robert ULg et al

in Polymer Degradation & Stability (2005), 90(2), 288-294

Nanocomposites based on an ethylene vinyl acetate copolymer (27 wt% vinyl acetate) and various (organo-modified) clays have been prepared by melt blending and their morphology, tensile and thermal ... [more ▼]

Nanocomposites based on an ethylene vinyl acetate copolymer (27 wt% vinyl acetate) and various (organo-modified) clays have been prepared by melt blending and their morphology, tensile and thermal degradation properties have been evaluated. Special attention has been paid to the influence of the clay nature and origin (montmorillonite or fluoromica) as well as on the nature of the ammonium cation organic modifier. It has been shown that nanostructure and tensile properties mainly depend on the nature of the organic modifier while the delay in thermal volatilisation of EVA during thermo-oxidation is mainly driven by the nature of the clay (mainly its aspect ratio), with no significant influence of the nanostructure of the nature of the organic modifier. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

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See detailPoly(methyl methacrylate)/graphene oxide nanocomposites by a precipitation polymerization process and their dielectric and rheological characterization
Thomassin, Jean-Michel ULg; Trifkovic, Milana; Alkarmo, Walid et al

in Macromolecules (in press)

We report a method for achieving controlled dispersion of graphene oxide (GO) in poly(methyl methacrylate) (PMMA) via the precipitation polymerization process in a water/ methanol mixture. GO acts as a ... [more ▼]

We report a method for achieving controlled dispersion of graphene oxide (GO) in poly(methyl methacrylate) (PMMA) via the precipitation polymerization process in a water/ methanol mixture. GO acts as a surfactant and adsorbs on the interface between polymerized PMMA particles and solvent mixture. Scanning electron and transmission electron microscopy confirmed that the precipitate consists of polymer particles (<1 μm) surrounded by the GO sheets. Compression molding of the precipitate yields a polymer nanocomposite with the GO organized into a regularly spaced 3D network which percolates at 0.2 wt % GO. Simple thermal reduction of the GO sheets dispersed in PMMA at relatively low temperature (210 °C) achieved electrical conductivity higher than 10−2 S/m at 0.4 wt % of GO. Parallel dielectric and rheological characterization demonstrated that the thermal reduction is a quite fast process without significant degradation of the polymer. The study should open up new opportunities in the design of GO-based polymer nanocomposites. [less ▲]

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