Reaction of maleic anhydride and molten polystyrene in the absence and presence of peroxides

Abstract

AbstractThermomechanical degradation of polystyrene (PS) at 180° and 250°C resulted in main chain scission and a small decrease in the molecular weight, as measured by inherent viscosity. The lower molecular weight was retained in the presence of maleic anhydride (MAH) although the latter was incorporated into the PS. The presence of benzoyl peroxide and dicumyl peroxide in the molten PS resulted in a significant molecular weight reduction, due to disproportionation of the internal radicals generated by hydrogen atom abstraction from the PS backbone. The extent of peroxide‐induced degradation was greatly reduced in the presence of MAH which presumably added to the internal PS radicals before their disproportionation. The low MAH content of the reaction product despite the use of high concentrations of MAH and peroxides is attributed to the quenching of MAH excimers by PS.