Compatibilization of polypropylene-polystyrene blends: Part 2, crystallization behavior and mechanical properties

Graft polymerization of styrene onto polypropylene chains generates polypropylene (PP) and polystyrene (PS) blends simultaneously. These reactor blends have a low impact resistance and have to be modified with the addition of rubbery toughening agents such as ethylene propylene copolymer (EPR) or styrene-g-ethylene-alt-butylene-g-styrene triblock copolymers (SEBS). Blend morphology is stabilized by the simultaneous formation of a graft copolymer which acts as a compatibilizer. In polymer blends with atleast one crystallizable component, the presence of other component can have significant influence on its melting and crystallization temperatures, crystallite growth rate, and crystallity.