THE EFFECT OF SHEAR ON THERMOTROPIC LIQUID-CRYSTALLINE POLYMERS

We present and review optical and theological data on a number of shea red thermotropic liquid crystal polymers LCPs. Optical observations we re carried out by using a shearing apparatus that was designed for the se and additional in situ X-tay measurements. X-ray data on sheared LC Ps are also presented together with orientation relaxation measurement s made on the cessation of flow. To reconcile the optical, X-ray and t heological data, a numerical scheme is constructed that can qualitativ ely, and in some cases quantitatively predict observed behaviour. Esse ntial elements of the model are concerned with a local molecular aniso tropy, a molecular correlation coefficient, and a local defect structu re. The model shows, among other predictions, that stress relaxation i s essentially decoupled from both orientation and optical relaxation. In addition the presence of a defect texture influences orientation as pects more than the theology.