Self-Reinforcing Polymer Blends Containing a Liquid Crystalline Polymer: Processing, Microstructure and Properties

Abstract

Blends of nylon-6,6 with a thermotropic liquid crystalline polymer (VECTRA) were processed by injection moulding. Tensile testing was carried out on specimens of blend compositions in the range of 20 to 30% VECTRA where specimens with 25% VECTRA presented the best Young’s modulus and strength. The fracture surfaces were examined in SEM and showed a skin/core morphology. The skin contained highly oriented fibrillar domains of VECTRA, the size and texture of which changed with blend composition. VECTRA displayed the best reinforcing properties when its fibrillar domains in the skin region were arranged into thick bundles of detectable fibrils. This marked the VECTRA concentration above which the VECTRA fibrils started coalescing into thicker fibres of smaller aspect ratio which reduced the reinforcing properties of VECTRA.