Melt rheology of nanometre-calcium-carbonate-filled acrylonitrile-butadiene-styrene (ABS) copolymer composites during capillary extrusion

摘要

The melt flow properties during capillary extrusion of nanometre-calcium-carbonate-filled acrylonitrile-butadiene-styrene (ABS) copolymer composites were measured by using a Rosand rheometer to identify the effects of the filler content and operation conditions on the rheological behaviour of the sample melts. The experiments were conducted under the following test conditions: temperature varied from 220 to 240 deg C and shear rate ranged from 10 to 10~4s~(-1). The filler volume fractions were 0,10,20,30, 40 and 50%. The results showed that the shear flow did not strictly obey the power law under the test conditions, and that the entry pressure drop (DELTAP_(en)) and the extension stress (sigma_e) in entry flow increased nonlinearly, while the melt viscosity (eta_s) and extension viscosity (eta_e) decreased with increasing the wall shear strees (tau_w) at constant test temperature. The dependence of the melt shear viscosity on the test temperature was approximately consistent with the Arrhenius expression at fixed tau_w. When tau_w constant, eta_s and eta_e increased with DELTAP_(en) and sigma_e decreased with the addition of the filler volume fraction.