From linear viscoelasticity to elongational flow of polydisperse linear and branched polymer melts: The hierarchical multi-mode molecular stress function model

Abstract

Abstract We developed a novel Hierarchical Multi-mode Molecular Stress Function (HMMSF) model for polydisperse polymer melts, which implements the basic ideas of (i) hierarchical relaxation, (ii) dynamic dilution, and (iii) interchain tube pressure. Here, the capability of this approach is demonstrated by comparison of predictions of the HMMSF model with uniaxial extensional viscosity data of sixteen different grades of high and low density polyethylene melts, as well as two different polystyrene melts with defined topology. The modelling is solely based on the linear-viscoelastic relaxation modulus with only one non-linear material parameter, the dilution modulus.