The influence of nanosilica on styrene free radical polymerization kinetics

Abstract

A series of nanocomposites were prepared by in situ polymerization of styrene with different silica content (1, 3, and 5 wt%) with an average particle size of 7 nm. The influence of nanosilica content on the kinetics of styrene free radical bulk polymerization was studied by isothermal differential scanning calorimetry (DSC) at different temperatures (70, 80, and 90°C). Using appropriate kinetic model, describing two reactions observed during styrene polymerization (the first-order reaction and autoacceleration), it was found that silica presence does not affect the apparent activation energies of both processes. The adsorption of styrene on the silica surface caused the formation of interfacial layer in the structure of hybrid materials. Using suggested equation, the thickness of the interfacial layer was determined to investigate its influence on the glass transition temperature of polystyrene (T g), which was found not to be affected by silica addition. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers.