Preparation of PBT/POE‐g‐GMA/PP ternary blends with good rigidity–toughness balance by core–shell particles

Abstract

ABSTRACTCompared with poly(butylene terephthalate)/glycidyl methacrylate grafted poly(ethylene–octene) (PBT/POE‐g‐GMA) binary blends, supertough PBT‐based ternary blends with little rigidity loss were successfully obtained by adding rigid polypropylene (PP) into PBT/POE‐g‐GMA blends to construct core–shell particles during melt blending. The effects of PP content and type on the phase morphology and mechanical properties of the blends were systematically investigated. Theoretical predictions and scanning electron microscopy observation showed that a core–shell structure was formed in PBT matrix with PP as the core and POE‐g‐GMA as the shell. The mechanical property tests showed that POE‐g‐GMA and PP had significant synergistic toughening effect. When PP with high melt flow index (H‐PP) was used, PBT/POE‐g‐GMA/H‐PP (70/15/15) blends possessed the highest Izod notched impact strength, which was 1.9‐fold compared with PBT/POE‐g‐GMA (70/30) binary blends, while the tensile performance loss was little. The essential work of fracture tests was performed to evaluate the fracture resistance of different samples. The results demonstrated that PBT/POE‐g‐GMA/PP ternary blends possessed much better resistance to crack propagation than PBT/POE‐g‐GMA binary blends. The decrease of interparticle distance and the fibrillation of core–shell particles activated intense matrix shear yielding, which was the reason for the high crack resistance of ternary blends. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48872.