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In situ polymerization and characterization of polyacrylate / silica systems

In situ preparation is the best procedure to achieve uniform distribution of nanofillers in polymer matrix, which is one of the most important factors that determine improvement of the properties. For successful in situ polymerization of emulsion it is necessary to achieve conditions in which the polymerization process will occur around nanofiller particles. This can be achieved by using nonionic surfactant, initiator that can adsorb on nanofiller surface or using silane as coupling agent. In this work, the aim was to synthesize stable emulsions by in situ polymerization of butyl acrylate (BA) and methyl methacrylate (MMA) with colloidal nanosilica (0-15 %wt) and to investigate influence of silica addition on the properties of emulsion and films. Emulsion polymerization in presence of nanofiller is very complex since stability is influenced by many factors. Some of them are analyzed within this work. Rheological behavior and particle size distribution of stable emulsions were determined, and particle morphology was analyzed using scanning electron microscope. Mechanical and thermal properties of nanocomposite films prepared from emulsions by casting method were investigated. Results indicate that colloidal silica nanofiller increase particle size of emulsion and significantly change rheological behaviour from Newtonian to pseudoplastic. Nanocomposite polyacrylate films exhibit better mechanical and thermal properties.

in situ; emulsion polymerization; polyacrylate; silica nanofiller

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