DefinePK

Abstract

Thermoplastic vulcanizates (TPVs) were prepared by melt mixing of polypropylene random copolymer (PPRC) and ethylene propylene diene rubber (EPDM). PPRC was grafted with the maleic anhydride to enhance the compatibility of PPRC and EPDM. The grafting was carried out by two different methods i.e. reactive (in-situ) and non-reactive (ex-situ) compatibilization. The synthesis method of blend affects mechanical properties and UV stability of blends. Extent of UV degradation was determined by measuring the carbonyl indexes of irradiated samples. Generally, blends prepared by reactive compatibilization had greater stability against UV light due to the morphology developed during compatibilization. DSC results showed higher crystallinity of TPVs prepared by reactive compatibilization. Increasing the amount of rubber resulted in more unsaturation level and ultimately higher carbonyl indexes obtained. Addition of large amount of filler in blends showed improvement in UV resistance. This may be attributed to formation of polymer-silane-silica network.