Grafting of Polystyrene Chains on Surfaces of Nanosilica Particles via Peroxide Bulk Polymerization

This article describes an in situ bulk polymerization process of styrene in the presence of silica nanoparticles. In this peroxide bulk polymerization process, two polystyrene fractions are formed: A polystyrene (PS) fraction attached to the particle's surface, which cannot be detached by hot xylene extraction, and an unattached PS fraction which dissolves in xylene. Solvent extraction and TGA measurements have confirmed the existence of grafted PS chains to the silica surfaces. FTIR measurements have indicated the existence of Si-O-C bonds connecting the PS grafts to the silica surface. Polypropylene (PP) was blended with the extracted PS-g-silica particles to produce concentrations of 1-3% nanoparticles in the PP composites. A remarkably improved dispersability of the nanoparticles was achieved, thus grafting reduces re-agglomeration and increases the affinity of the grafted surface to the polymer matrix. POLYM. COMPOS., 30:422-428, 2009. (C) 2008 Society of Plastics Engineers