Thermal behavior, morphology, and some melt properties of blends of polycarbonate with poly(styrene-co-acrylonitrile) and poly(acrylonitrile-butradiene-styrene)

Blends of bisphenol-A polycarbonate (PC) with poly(styrene-co-acrylonitrile) (SAN) and poly(acrylonitrile-butadiene-styrene) (ABS) prepared by screw extrusion and solution-casting were investigated by differential scanning calorimetry and scanning electron microscopy. From the measured glass-transition temperatures (T_g) and specific heat increments (ΔC_p) at the T_g. SAN appears to dissolve more in the PC-rich phase than does PC in the SAN-rich phase. From the T_g behavior and the electron microscopy study, it is suggested that the compatibility increases more in the SAN-rich compositions than in the PC-rich compositions of the blends. In the study of extrudate swell of the PC/SAN blends and the PC/ABS blends, the maximum level of extrudate swell is reached at 0.5 weight fraction of PC for both blend systems. The Flory-Huggins polymer-polymer interaction parameter between PC and SAN was calculated and found to be 0.034±0.004. A similar value for PC and SAN was found with the PC/ABS blends.