Structure and mechanical properties of new hybrid composites based on polyamide 6,6 reinforced with both glass fibers and a semiaromatic liquid crystalline polyester

Polyamide 6,6 (PA66) composites with 30% glass fiber (GF) were blended with a semaromatic liquid crystalline copolyester (Rodrum 5000 (R5)) up to 40% R5 by injection molding. The composites showed two amorphous phases. Interchange reactions took place between the two polymers, leading to good interfacial adhesion. The addition of 20% R5 was enough to counteract the viscosity increase provided by the GF. The synergistic increases in the modulus of elasticity were attributed to the increase in the skin thickness at increasing R5 content. The tensile strength of the composites remained constant on LCP addition, despite the lower tensile strength of R5 compared with that of PA66/GF. The notched impact strength increased notably at increasing R5 content. (C) 2004 Society of Plastics Engineers.