PROPERTIES AND MORPHOLOGY OF POLYAMIDE-6 HYBRID COMPOSITES CONTAININGPOTASSIUM TITANATE WHISKER AND LIQUID-CRYSTALLINE COPOLYESTER

Polyamide 6 (PA6) hybrid composites reinforced with potassium titanate whiskers (K2Ti6O13) and liquid crystalline polymer (LCP) were prepare d in a twin-screw extruder followed by injection moulding. The whisker s were surface treated with tetrabutyl orthotitanate prior to blending . Static tensile measurements showed that the tensile strength and mod ulus of the composites tend to increase with increasing whisker conten t. However, Izod impact tests indicated that the hybrid composites sho w little variation in the impact strength with the addition of whisker content up to 10 wt%, thereafter the impact energy shows an obvious d ecrease with increasing whisker content. Scanning electron microscopic observations revealed that the oriented LCP fibrils were formed in th e skin section of hybrid composites containing whisker content < 10 wt %, whilst spherical droplets were dispersed in the skin section of hyb rids containing whisker content greater than or equal to 15 wt%. Torqu e measurements showed that the LCP is very effective in reducing the m elt viscosities of PA6/K2Ti6O13 composites. Finally, thermogravimetric analysis showed that the hybrid composites with higher whisker conten t exhibit good heat resistance properties. The hybrid effects of the t wo reinforcements on the mechanical properties and compatibility of th ese hybrid composites are discussed. (C) 1998 Elsevier Science Ltd. Al l rights reserved.