Effect of core–shell structures of acrylonitrile–styrene–acrylate (ASA) terpolymer on the properties of poly(vinyl chloride) (PVC)/ASA blends: Miscibility, toughness, and heat resistance

In this work, acrylonitrile–styrene–acrylate (ASA) terpolymer was used to toughen rigid poly(vinyl chloride) (PVC). ASA has a core–shell structure, where the poly(butyl acrylate) (PBA) serves as the soft core while styrene-acrylonitrile (SAN) copolymer works as the rigid shell. Herein, The PBA core content in ASA was varied from 0 to 80 wt %, and its effect on the physiochemical properties was investigated. It was found that the hard shell of ASA was miscible with PVC matrix, providing good interfacial adhesion between ASA and PVC. Increasing the soft PBA content considerably improved the room-temperature impact toughness, and a sharp brittle–ductile transition (BDT) as a function of PBA content was observed. However, as the testing temperature decreased to 0 and −30 °C, the toughening effect became limited, and the BDT first shifted to high PBA content region and finally disappeared. It was suggested that whether the toughening effect can be achieved depended on the thickness of hard shell and the relaxation behavior of PBA core. Albeit the loss in rigidity was accompanied, the accomplished toughening effect was not on the sacrifice of heat distortion temperature.