GEOMETRY DEPENDENCE OF THE VISCOSITY OF A THERMOTROPIC LC-POLYMER MEASURED BY SLIT DIES

This paper reports on geometry dependent viscosity curves of the biaxi al thermotropic LC-Polymer Vectra B 950 measured with rectangular slit dies. The geometry dependence of the flow behaviour originates from t he flow of two layers. The layer near the wall is highly flow oriented and free from defects. The layer in the bulk has an ordered texture. The thickness of the wall layer decreases with wall shear stress. Base d on the Frank theory and the assumption that the core of a moving dis clination is the smallest radius of distortion, the wall layer thickne ss is predicted and compared with experimental data.