Compatibilization and mechanical properties of compression-molded polypropylene/high-impact polystyrene blends

Abstract

This research work focused on polypropylene/high-impact polystyrene polymer blends. Since this blend (80/20 in weight) was incompatible, styrene–ethylene–butylene–styrene (SEBS) block copolymer, styrene–butadiene–styrene (SBS), and ethylene vinyl acetate were tested as compatibilizers (2.5 or 7.5 wt% in relation to blend). After blending via extrusion, the compositions were compression molded and their mechanical (tensile and impact), morphological (scanning electron microscopy), and rheological (melt flow index and viscosity) properties were evaluated. Blends containing SBS and 7.5 wt% of SEBS showed a positive effect regarding impact strength, although with a decrease in Young’s modulus and tensile strength. Rheological characteristics were also affected by the compatibilizers.