New viscoelastic fluid theory based upon the concept of an intermediate state

Abstract

The kinematical basis of modern plasticity, namely the multiplicative composition law of elastic and non-elastic deformation gradients, is detached from its usual connection to the internal state variables of plasticity, thus rendering a new general thermomechanical theory of finite deformations which comprises rheology, too. Assuming most simple material properties, the theory is applied to the steady simple shear flow. Not only qualitatively correct viscometric functions of concentrated polymer solutions and melts are derived, but also the possibility of an infinite-shear-rate viscosity, as well as the possibility of dilatancy beside pseudoplastic behaviour.