Non‐linear Step Strain of Branched Polymer Melts

摘要: The Pom‐pom model by McLeish and Larson (Journal of Rheology 42(81–110), 1998) is a highly successful molecular theory for describing the rheology long chain branched melts. However, there long‐standing puzzle in step strain: how can that intrinsically non‐separable recover empirical strain‐time separation? We investigate step‐strain, comparing qualitatively different behaviour single mode integral differential orientation. Despite this difference when both models are used multi‐mode form, their shown to be comparable. Although neither nor predict exact time‐strain separability, create region which approximation very good one before longest stretch time has been reached.By transforming continuous spectrum we find under certain assumptions, parameter sub‐space where an analytic damping function derived. survey range materials produced two syn...