Time-Dependent Flows of Dilute Solutions of Rodlike Macromolecules

Abstract

For a suspension of rigid macromolecules with Brownian motion, expressions are obtained for the components of the stress tensor for any time‐dependent shearing flow. The results are expressed up to terms of the fourth order as a series of memory integrals. The first two terms in the series enable one to calculate the explicit expressions for the kernel functions for second‐order viscoelasticity. It is established that the Oldroyd six‐constant model does not give kernel functions which are of the same form as those given by the molecular theory of rigid macromolecules. The general time‐dependent elongational flow results are also given through terms of the third order.