Blends of poly(vinyl chloride) with α-methylstyrene-acrylonitrile- butadiene-styrene copolymer: Thermal properties, mechanical properties, and morphology

Binary blends of poly(vinyl chloride) (PVC) with α-methylstyrene- acrylonitrile-butadiene-styrene copolymer (AMS-ABS) were prepared via melt blending. A single glass transition temperature (T_g) was observed by differential scanning calorimetry, thus indicating that PVC is miscible with the α-methylstyrene-acrylonitrile-styrene in AMS-ABS. The results from attenuated total reflection Fourier transform infrared spectra indicated that specific strong interactions were not available in the blends. With increasing amounts of AMS-ABS, both heat distortion temperature and thermal stability were increased considerably. With regard to mechanical properties, flexural and tensile properties decreased with increasing AMS-ABS content. A synergism was observed in impact strength. The morphology of both impact-fractured and tensile-fractured surfaces, observed by scanning electron microscopy, correlated well with the mechanical properties. It is suggested that there was a transition of fracture mechanisms with the changing composition of the binary blends - from shear yielding for blends rich in PVC to cavitation for blends rich in AMS-ABS.