Investigation of the Influence of Red Phosphorus, Expansible Graphite and Zinc Borate on Flame Retardancy and Wear Performance of Glass Fiber Reinforced PA6 Composites

The flame retarded materials were prepared which used wear-resistant PA6 composite (PA6/GF/PTFE/UHMWPE/CG, 85/15/5/5/5 by weight) as matrix, red phosphorus (RP), expansible graphite (EG), and zinc borate (ZB) as fire retardant. The flame retarded properties were characterized by LOI and UL-94 testing. PA6 composite with 15 wt% RP reached V0 rating and had a high LOI value (27.3 vol%). When a combination of 7 wt% ZB and 8 wt% RP was added, increases in LOI (27.9 vol%) and UL-94 rating(V0) were both observed. Thermogravimetric analysis (TGA) and char residue characterization showed that the combination of RP and ZB can promote the formation of char barrier, reduce the mass loss rate, and thus improve the flame retardancy of PA6 composites. The wear test showed that, the composite filled by 15 wt% RP or a combination of 7 wt% ZB and 8 wt% RP both possessed a low wear rate and a much stable friction coefficient. The presence of EG could also improve the flame retardance but was harmful to the mechanical property as well as wear performance. The results indicated that ZB and RP had synergy effect on improving both flame retardance and wear performance of PA6 composites. (C) 2015 Society of Plastics Engineers