Nonlinear Rheology of Polymer Melts under Shear Flow

Abstract

The nonlinear theology of an unentangled polymer melt under shear flow is considered theoretically. The finite chain extensibility is taken into account explicitly. The tangential stress and the first and the second normal-stress differences are calculated as a function of shear rate gamma. It is shown that in the shear thinning regime, the viscosity eta decreases as gamma(-23).