The rheological properties of polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blends with various blend ratios are investigated at different temperatures to determine the shear dependent chain motions in a heterogeneous blend system. At low frequency levels under 0.1 rad/s, the viscosity of the material with a blend ratio of 3:7 (PC:ABS) is higher than that of pure ABS polymer. As the temperature increases, the viscosities of ABS-rich blends increase rather than decrease, whereas PC-rich blends exhibit decrease in viscosity. Results from the time sweep measurements indicate that ordered structures of PC and the formation and breakdown of internal network structures of ABS polymer occur simultaneously in the blend systems. Newly designed sequence test results show that the internal structures formed between PC and ABS polymers are dominant at low shear conditions for the blend ratio of 3:7 and effects of structural change and the presence of polybutadiene (PBD) become dominant at high shear conditions for pure ABS. The results of yield stress and relaxation time for PC/ABS blends support this phenomenon. The specimen with a blend ratio of 3:7 exhibited the highest value of yield stress at high temperature among others, which implies that the internal structure become stronger at higher temperature. The heterogeneity of ABS-rich blends increases whereas that of PC-rich blends decreases as temperature increases.
The morphologies and physical properties of twin‐screw‐extruded polycarbonate/acrylonitrile‐butadiene‐styrene (PC/ABS) blends with various blend ratios are studied. The needle‐like co‐continuous phase in PC‐rich blends changes to the sea‐island phase for blend ratios of more than 50 wt% ABS. While pure PC exhibits an almost‐Newtonian flow behavior, PC/ABS blends exhibit the interesting rheological transition. The viscosities of the ABS‐rich blends at low shear rates are almost equal to those of the pure ABS polymer. The yield stress for the PC/ABS blend ratio of 3:7 is the highest in composition. At the frequency of 10 rad/s, the PC‐rich blends exhibit highly viscous properties, whereas the ABS‐rich blends present highly elastic properties as the temperature increases. Moreover, the ABS polymer in the PC/ABS polymer blend induces significant change at the fracture surface of PC, transitioning from brittle to ductile nature.
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