The free-radical cotelomerization of 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) with perfluorodecylacrylate (PFDA) in the presence of 2-mercaptoethanol was performed at 80°C in acetonitrile. Hydroxy end-groups of the cotelomers were reacted with 2-isocyanatoethyl methacrylate (IME) to give macromonomers. The P(TMSPMA-stat-PFDA) cotelomers, containing fluoro and silane groups, were then grafted onto silica nanoparticles. Optimal grafting conditions were found with TMSPMA monomer alone in toluene at 110°C. The structure of the modified silica was analyzed by FTIR and 29 Si solid-state NMR. The amount of grafted TMSPMA or P(TMSPMA-stat-PFDA) was calculated by thermogravimetric and elemental analyses. The grafting yield increased with the copolymer/silica weight ratio until a maximum value of 2.26 μmol.m -2 .

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A series of polyamides based on Z‐octadec‐9‐enedioic acid, a bio‐based unsaturated monomer, and aliphatic‐, cycloaliphatic‐, or benzylic diamines were synthesized and characterized by 1H and 13C NMR analysis, size exclusion chromatography (SEC), DSC, and dynamic‐mechanical analysis (DMA). The high reaction temperature (250 °C) did not lead to the degradation of diacid unit double bonds and unsaturated polyamides were obtained. The aliphatic unsaturated polyamides are semi‐crystalline polymers of high molar mass, relatively flexible at room temperature. The cycloaliphatic unsaturated polyamides are semi‐crystalline or amorphous, present higher melting and glass transition temperatures and are much more rigid. The aliphatic and aliphatic–aromatic unsaturated polyamides present lower Tg and Tm as compared to their parent saturated polymers.magnified image

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International audienceThis article is devoted to the effects of the presence of modified clays during in-situ polymerization. Such synthesis routes require clay modifications in order to render the clay surface compatible with the monomer-polymer and/or reactive during polymerization. In addition, the use of nanometric clays (laponite) induces a large surface area which introduces the differentiation between the polymer located in the clay vicinity (interphase) and the bulk polymer. Composite nanoparticles obtained from in-situ emulsion and from in-situ-miniemulsion polymerizations and simple blends of pure polymer latex and unmodified clays were used to prepare free-standing films. The behavior of these composite films has been compared in terms of shifts in relaxation temperature (assessed by Dynamic Mechanical Analysis), in monomer composition (assessed by Nuclear Magnetic Resonance analysis) and in molecular weight (assessed by Gel Permeation Chromatography). It has been demonstrated that both nanocomposites obtained by in-situ polymerization show a modification of the relaxation process due in the case of emulsion to a composition drift in the vicinity of the clay, and in the case of miniemulsion to a plasticizing effect of the numerous short copolymer chains generated at the clay surface. (C) 2010 Elsevier Ltd. All rights reserved

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