A Molecular Theory of Stress Relaxation in Polymeric Media

The application of the kinetic theory of rubber elasticity to the description of the relaxation of cross-linked networks is only permissible in cases where the rate determining process is slow compared to the rate of diffusion of the polymer chains. Relaxation resulting from chemical reactions causing breaking of network crosslinks and formation of new crosslinks is a process of this type. In this paper, a differential equation is proposed which describes the rate of relaxation in terms of the rates of the molecular processes. A simplified solution of this equation is given, and the consequences of the solution are discussed.