Abstract: Emulsion co-polymerization of St/BAin the presence of inorganic SiO₂ nanoparticles was studied. Firstly, the most effective emulsifiers for this emulsion copolymerization were chosen. Then, the influence of temperature and SiO₂ content on conversion were studied and the results convicted that SiO₂ could reduce the conversion of monomer. By SEMit was proved that SiO₂ had been encapsulated into emulsoid of St/BAand SiO₂ could influence the fracture structure of emulsion polymer. Residues appeared during the polymerization, this phenomenon was researched by elemental analysis. The mechanical and thermal properties of composites were measured to find that SiO₂ content had great influence on these properties. In the end an improved emulsion polymerization process by beforehand emulsifying SiO₂ nanoparticles was presented and a better result was obtained.

Key words: Emulsion co-polymerization of St/BA, SiO₂ nanoparticle, Inorganic-polymer nanocomposites