2014 Volume 26 Issue 2 Pages 93-99
It is well known that melt-blending of polypropylene (PP) with polycarbonate (PC) without a third component has very poor mechanical properties. That is, the tensile properties of PP are seriously weakened by blending the tougher component (PC). We found that, by adding hydrogenated styrene-butadiene-styrene block copolymer (SEBS) as a third component, the mechanical properties were remarkably improved; i.e., the PP/PC/SEBS (especially low molecular weight SEBS) ternary blend, e.g., at 60/40/10 wt. ratio, showed large elongation at break and high Izod impact strength. In the ternary blend, SEBS was dispersed as the fine particles (ca. 100nm diameter) in PP matrix and also as the interface layer between PP matrix and PC particles. FEM analysis showed that the SEBS shell at the interface enhanced the stress concentration in PC core parts, leading to a ductile deformation of the rigid particle (PC) in the ductile matrix (PP).
