Molecular-based Models for Viscoelasticity of Polymers

Abstract

Various models are developed to describe several different aspects of the dynamics of polymers. First, a model is developed which describes the dynamics of a single polymer chain, residing in a viscous fluid, in response to various stimuli. Next, constitutive models leading to reptation are developed, which determine the stress-strain relations for a system of physically constrained (PC) molecules residing within a chemically cross-linked (CC) system of molecules acting as a constraining tube for the PC system. These reptation models treat relaxation within the context of both intra-molecular and inter-molecular variability. Finally, a model is developed which combines the Rouse model of relaxing polymers and the stick-slip reptation model. This stick-slip/Rouse hybrid model incorporates parameters which were ignored in models developed in the earlier parts of the dissertation.