Effects of mixing procedure on the morphology and properties of poly(ether imide)/thermotropic copolyester blends

Poly(ether imide)/thermotropic copolyester (Rodrun) blends with liquid crystalline polymer contents of 5, 20 and 40% were obtained by injection moulding, both with and without previous extrusion, and at different melt temperatures and injection speeds. Previous extrusion or different injection speeds changed neither the morphology nor the mechanical properties of the blends, which improved significantly only at higher temperatures. The lack of significant increase in properties was due to the very low viscosity ratio-induced lack of fibrillation and overall poor mixing level of the blends, which was seen even in blends injected after previous extrusion. (C) 1999 Elsevier Science Ltd. All rights reserved.