BLENDS OF A THERMOTROPIC LCP AND A THERMOPLASTIC ELASTOMER .2. FORMATION AND STABILITY OF LCP FIBERS

The formation of fibers during blending of a thermotropic liquid cryst alline polymer (LCP) with a thermoplastic elastomer (TPE) using shear flow, and the stability of the fibers and the blend morphologies at el evated temperatures were studied. The polymers used were Vectra A900 ( LCP) and Kraton G1650 (TPE). Fiber formation in (predominantly) shear flow was studied using a single screw extruder of which the die was re moved. Fibers were obtained in blends with 5 vol% LCP at shear rates a s low as 6.3 s-1. Conventional extrusion through a die was used for pr eparing materials for the studies of the thermal stability of blends a nd isolated fibers-isolated LCP-fibers surrounded by a TPE-matrix disi ntegrate when held above the melting point of the LCP. Annealing of th e blends at this melting temperature results in changes of the morphol ogy and in a fairly rapid decrease of the modulus of elasticity.