Studies on binary and ternary blends of polypropylene with SEBS, PS, and HDPE. II. Tensile and impact properties

摘要

AbstractStudies are reported on tensile and impact properties of several binary and ternary blends of polypropylene (PP), styrene‐b‐ethylene‐co‐butylene‐b‐styrene triblock copolymer (SEBS), high‐density polyethylene (HDPE), and polystyrene (PS). The blend compositions of the binary blends PP/Xwere 10 wt Xand 90 wt PP, while those of the ternary blends PP/X/Ywere 10 wt ofXand 90 wt of PP/Y, or 10 wt Yand 90 wt PP/X(PP/Yand PP/Xwere of identical composition 90:10);X, Ybeing SEBS, HDPE, or PS. The results are interpreted for the effect of each individual component by comparing the binary blends with the reference system PP, and the ternary blends with the respective binary blends as the reference systems. The ternary blend PP/SEBS/HDPE showed properties distinctly superior to those of PP/SEBS/PS or the binary blends PP/SEBS and PP/HDPE. Differences in the tensile yield behavior of the different samples and their correlation with impact strength suggested shear yielding as the possible mechanism of enhancement of impact strength. Scanning electron microscopic study of the impact fractured surfaces also supports the shear yielding mechanism of impact toughening of