A CONSTITUTIVE EQUATION FOR MONODOMAINS OF NEMATIC POLYMERS

Based on the rigid-rod model, a constitutive equation for liquid-crystalline polymers (LCPs) is presented. The constitutive equation is formulated in terms of a fourth-rank tensor, to which stress is related. The equation was obtained from the diffusion equation for the orientational distribution function by making use of a closure approximation at the level of the sixth-order moments of the distribution. Although no spatial inhomogeneities are considered, most of the peculiar rheological behaviour experimentally determined for LCPs is qualitatively predicted.