Rheological predictions of network systems swollen with entangled solvent

Abstract

The mechanical properties of a cross‐linked polydimethylsiloxane (PDMS) network swollen with nonreactive entangled PDMS solvent was previously studied experimentally. In this article, we use the discrete slip‐link model to predict its linear and nonlinear rheology. Model parameters are obtained from the dynamic modulus data of pure solvent. Network rheology predictions also require an estimate of the fraction and architecture of dangling or inactive strands in the network, which is not directly measurable. The active strand fraction is estimated from dynamic modulus measurements, and the molecular weight is adjusted to fit the dynamic modulus data. Then, the nonlinear rheology can be predicted without adjustments. These successful predictions strongly suggest that the observed rheological modification in the swollen blend arises from the constraint dynamics between the network chains and the dangling ends. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1372–1380, 2014We dedicate this article to Prof. R. Byron Bird on the occasion of his 90th birthday. We attempt to follow the twin exhortations of Bob to be both mathematically rigorous and practically relevant.