Mechanistic differences in degradation of polystyrene and polystyrene-clay nanocomposite: Thermal and thermo-oxidative degradation

A conceptual model for degradation of polymer-clay brushes is discussed. The model predicts enhancement of inter-molecular reactions and slowing down of molecular mobility. A polystyrene (PS)-clay brush system is experimentally compared with virgin PS under the conditions of thermal and thermo-oxidative degradation. GC-MS and TGA-FTIR analysis of the gas phase degradation products of PS-clay composite confirm a dramatic increase in the yield of inter-molecular reaction product, such as alpha-methylstyrene. Combining DSC measurements with FTIR analysis of condensed phase thermo-oxidative degradation of PS-clay suggests that PS-clay nanocomposite is more stable to oxidation, however, oxidation products tend to accumulate in it because of slowing down diffusion of oxidation products.