Izod impact strength at low temperature of poly(vinyl chloride)/methyl methacrylate/butadiene/styrene polymer blends

Izod impact strength and fracture behavior of poly(vinyl chloride) (PVC)/me thyl methacrylate/butadiene/styrene polymer (MBS) blends were studied with different kinds of MBS whose components were a wide variety. Both shear yie ld and crazing occurred in the whitened area of Izod test pieces, while cra zing only occurred in non-whitened area at Izod impact test at both room an d low temperature. In the case of Izod impact test at room temperature, imp act strength was closely related to the whitened area and degree in test pi eces, and improved with increasing whitened area and degree. On the other h and, at low temperature, Izod impact strength was closely related to whiten ed area. Based on such results the fracture mechanism of the Izod test was considered. And it was proved that the yield stress, which was related to w hitened area and ease of transition to shear yield, was very important in c ase of Izod test at low temperature. The amount of energy which was absorbe d by yield stress decreased the crack speed and influenced the whitened are a at room temperature.