SYNOPSISThe melt viscosity of polycarbonate/acrylonitrile-butadiene-styrene ( PC / ABS ) blends relative to PC is significantly lower, even lower than that of pure ABS in some compositions. Annealing above the TB of PC coalesces and coarsens phase structure in core and skin regions. Increase in the molecular weight of PC in PC /ABS blends results in low-temperature fracture toughness improvement but suffers from the disadvantage of higher melt viscosity. The selection of PC in PC/ABS blends must be a compromise between the toughness advantages of higher PC molecular weight and the disadvantages of higher melt viscosity.

ABSTRACT:Higher ABS rubber content in the polycarbonate (PC)/acrynitrile-butadienestyrene (ABS) blend resulted in toughness improvement in terms of tensile, Izod impact and strain energy release rate at a cost of higher melt viscosity. The extra-added core-shell rubber particles with poly(methyl methacrylate) (PMMA) or acrylonitrile-styrene (SAN) outer shell resided mainly in the ABS phase and further improved the resulted blends to11ghness. The addition of styrene-maleic anhydride (SMA) copolymer in the PC/ABS blends caused severe coagulation of the rubber particles in the ABS phase and left a greater fraction of the SAN phase without presence of rubber. The toughness improvement by increasing rubber content must be compensated by the increase of melt viscosity and this fact has to be taken into consideration in selecting the starting materials of the PC/ABS blends.