Viscoelastic properties of entangled polymers. II. The interchain–intrachain entanglement model

Abstract : Our earlier model of entangled chain dynamics represented the elastic effects at entanglement points as a coupling with the surrounding medium, which was propagated weakly to every other entanglement site on the parent chain. In this way, a great variety of linear viscoelastic phenomena could be successfully predicted, with the only significant deficiency being a quantitative failure in curve-fitting the local minimum in dynamic loss modulu, G(omega). Here we introduce the 'intrachain entanglement' or the 'internal entanglement' in which the parent chain entangles directly with itself. Elastic forces between pairs of internal entanglements are assumed to be stronger than those with the medium ('external entanglements'). Predictions of the new model are compared with rheological data on monodisperse polystyrene. Good agreement was obtained between theory and experiment, including G(omega). (Author)