Rheology, morphology and properties of LCP/Nylon 66 composite fibers

The rheology, morphology and properties of the composite systems of LCP, Ve ctra A(TM) 950 and Nylon 66 were investigated. The viscosity ratio of LCP a nd matrix has strong influence on their morphology. For LCP blends, the vis cosity ratio of LCP is a critical factor in determining the blend morpholog y. The optical micrographs show that the good fibrillation can be achieved when the viscosity of the dispersed LCP phase is less than that of the Nylo n 66 matrix at 310 degrees C. The dispersed LCP domains tend to be spherica l or cluster-like when the viscosity ratio of the dispersed LCP phase and t he Nylon 66 matrix is more than 1 at 280 degrees C. The scanning electron m icroscopy (SEM) and optical micrograph observations show that Nylon 66 is i mmiscible with LCP, and there are two distinct phases in the blends. The mo rphology of LCP phase changes with the composition. LCP exhibits a fine fib ril dispersed phase in the Nylon 66 matrix in the law LCP concentration. Wi th an increase in LCP concentration, the morphology of LCP phase is changed from a fine fibril dispersed phase to a perfectly aligned continuous fiber reinforced phase in the rich LCP concentration. The tensile moduli increas e with LCP concentration, especially in the rich LCP concentration. The ten sile strengths increase with ICP concentration only when LCP concentration is above 40 wt%. Compared to the pure Nylon 66 fiber, the 40 wt% LCP compos ite sample shows a 982.1% increase in tensile modulus and a 123.3% increase in tensile strength. The mechanical properties of composite fibers are bel ow the rule of mixtures if the LCP concentration is low, but above the rule of mixtures if the LCP concentration is high.