Principles of the van der Waals network concept: Time‐dependent processes

Abstract

AbstractThe leading ideas behind the van der Waals modification of the Gaussian network are explained including a discussion of the meaning of the van der Waals parameters. The utility of approach is demonstrated in terms of a representation of deformations, of networks under different strains and of the heat exchanged during extension. The interpretation of stress‐strain experiments carried out on bimodal end‐linked model networks leads to a characterization of the width of the chain‐length distribution in rubbers. Finally, it is shown that the non‐linear visco‐elastic response in stress‐strain cycles of natural rubber can be understood within the framework of the classical thermodynamics of irreversible processes. The time dependent stress‐strain behaviour is fairly well described in the temperature regime of rubber‐elasticity by using a discrete small‐strain shear‐relaxation spectrum.