Synergistic toughening effect of chlorinated polyethylene and ethylene-vinyl acetate copolymer on the poly (vinyl chloride)/poly (α-methylstyrene-acrylonitrile) blends via compatibilization

Abstract

Poly (vinyl chloride) (PVC)/poly (α-methylstyrene-acrylonitrile) (α-MSAN) (70/30) blends was toughened by blending with chlorinated polyethylene (CPE) and ethylene-vinyl acetate copolymer (EVA). EVA did not improve the impact strength appreciably. A prominent synergistic toughening effect was observed when EVA and 15 phr CPE were used in combination in PVC/α-MSAN (70/30) matrix. A sharp brittle–ductile transition in impact strength was observed in the range of 1–5 phr EVA. With the addition of 5 phr EVA, the impact strength increased almost 24 times compared with that of PVC/α-MSAN (70/30) blends. Morphology was used to investigate the toughening mechanism, and the synergistic effect can be attributed to better compatibility between phases, and to the formation of a network structure of the dispersed-phases. The improved compatibility was also supported by differential scanning calorimetry results. Heat distortion temperature remained almost unchanged over all the compositions, indicating that the improvement in toughness did not sacrifice heat resistance.