Modeling the linear viscoelastic properties of metallocene-catalyzed high density polyethylenes with long-chain branching

The hierarchical model modified by Park et al. (2005) is applied to single-site metallocene-catalyzed high density polyethylene (mHDPE) to predict the effect of long-chain branching (LCB) on the linear viscoelastic properties. In this work we generate the distributions of molecular weight and LCB of mHDPE for the hierarchical model predictions using a Monte Carlo simulation of Costeux et al. (2002), where the simulation parameters are obtained from the average molecular weight and the degree of LCB. The parameters needed in the hierarchical model are determined from experimental data for linear polyethylenes. The model predicts the experimental data well, reveals the effect of LCB on the linear viscoelastic properties of mHDPE, and indicates the possibility of inferring branching levels from measurements of linear viscoelastic properties of mHDPEs. (c) 2005 The Society of Rheology.