Effects of extrusion conditions on rheological behavior of acrylonitrile-butadiene-styrene terpolymer melt

The influence of temperatures and flow rates on the rheological behavior during extrusion of acrylonitrile-butadiene-styrene (ABS) terpolymer melt was investigated by using a Rosand capillary rheometer. It was found that the wall shear stress (tau(omega)) increased nonlinearly with increasing apparent shear rates and the slope of the curves changed suddenly at a shear rate of about 10(3) s(-1), whereas the melt-shear viscosity decreased quickly at a tau(omega) of about 200 kPa. When the temperature was fixed, the entry-pressure drop and extensional stress increased nonlinearly with increasing tau(omega) whereas it decreased with a rise of temperature at a constant level of tau(omega). The relationship between the melt-shear viscosity and temperature was consistent with an Arrhenius expression. The results showed that the effects of extrusion operation conditions on the rheological behavior of the ABS resin melt were significant and were attributable to the change of morphology of the rubber phase over a wide range of shear rates. (C) 2002 Wiley Periodicals, Inc.