AbstractIn order to elucidate the role of reentanglement processes in the rheology of molten polymers, we have used the interrupted shear test and the reduction‐;in‐;shear‐;rate test to study a linear and a branched polyethylene at 170°C. A cone‐;plate rheometer was used, and shear rates were thus limited to values below 1 sec−1. For both polymers, the characteristic time for reentanglement was found to be significantly greater than the time scales associated with the relaxation of shear and normal stresses after cessation of steady shear. This observation has important implications for the modelling of melt flow in plastics processes and the evaluation of constitutive
展开▼
