Thermally conductive and flame-retardant polyamide 6 composites

Abstract

In order to satisfy the requirements of heat dissipation and fire safety in electric and electronic industries, polyamide 6 composites with high thermal conductivity, and excellent flame retardant property were manufactured by twin-screw extruder. Brominated polystyrene/antimonous trioxide and red phosphorus masterbatch/magnesium hydroxide synergistic flame retardants were used as flame retardant additives respectively, alumina and flaky graphite were used as thermally conductive fillers in the polyamide 6 composites. Effects of flame retardants and thermally conductive fillers on thermal conductivity, mechanical properties, and flammability of the polyamide 6 composites were investigated. The results showed that thermal conductivity of the polyamide 6 composites was mainly influenced by thermally conductive fillers and it was influenced slightly by flame retardants. Thermally conductive fillers had obvious effects on flame retardant efficiency of brominated polystyrene/antimonous trioxide flame retardant, while they had little impacts on flame retardant efficiency of red phosphorus masterbatch/magnesium hydroxide flame retardant. The tensile strength and flexural strength increased when alumina was filled into the polyamide 6 composites with either brominated polystyrene/antimonous trioxide or red phosphorus masterbatch/magnesium hydroxide flame retardants. The polyamide 6 composite with red phosphorus masterbatch/magnesium hydroxide and flaky graphite passed UL94-1.6 mm V-0 grade and its thermal conductivity could achieve 2.50 W/(m·K) in this study.