MECHANICAL-PROPERTIES OF IN-SITU COMPOSITES BASED ON POLYCARBONATE AND A LIQUID-CRYSTALLINE POLYMER

The mechanical properties of in situ composites based on blends of polycarbonate and a liquid crystalline copoly(ester amide) (Vectra B950) have been studied as functions of the liquid crystalline polymer (LCP) concentration and the draw ratio, a processing parameter. It is shown that both the elastic modulus and the tensile strength of the in situ composites increase steadily with the LCP concentration and the draw ratio. However, the ultimate tensile strain decreases with these two parameters. A model is proposed for the longitudinal elastic modulus of the in situ composites, which is based on the Halpin-Tsai equation and Northolt's model for the LCP phase. The experimental elastic moduli of the in situ composites are found to conform fairly well with the theoretical values derived from the model.