LOCALIZATION OF STYRENE-BUTADIENE BLOCK-COPOLYMERS IN POLYSTYRENE POLYPROPYLENE BLENDS/

Structure of polystyrene/polypropylene, PS/PP, blends compatibilized b y styrene-butadiene and styrene-butadiene-styrene block copolymers was studied by small-angle X-ray scattering and transmission electron mic roscopy. The results are compared with those obtained previously for a similar blend (HIPS/PP) where the PS phase contains polybutadiene, PB , inclusions. It is shown that the triblock influences formation of in terfacial layer in both blends in much more pronounced way than the di block. This results in improvement of impact strength and elongation a t break in the blends compatibilized by the triblock copolymer. In HIP S/PP blends, PB inclusions have no influence on the compatibilization efficiency of both block copolymers but they improve mechanical proper ties due to the toughness modifier action of PB in the PS phase.