A Study On Halogen-free Flame Retardant Kenaf Reinforced Poly(Lactic Acid) Composites

In this paper, the surface of kenaf fiber was modified. The modified kenaf fiber and the aromatic phosphate flame retardant were melting blended with poly (lactic acid) (PLA). Three flame retarded and reinforced systems were prepared, including PLA/modified kenaf/PX-220, PLA/modified kenaf/PX-220/FB88#, RDP/ZnO/kenaf ternary self-assemble system flame retarded and reinforced poly (lactic acid) composites.In the PLA/modified kenaf/PX-220 system, the modified kenaf fiber acted as reinforcing material, and the optimum amount of it determined through the comparison of the tensile strength of different addition amount of modified kenaf fiber in the composites was 10 wt%, with remarkable enhancing effect; then PX-220 was chosen as a single flame retardant to flame retard the kenaf reinforced poly (lactic acid) composites. It was found that PX-220 significantly improved the heat resistance and flame retardancy of the composites.In the PLA/modified kenaf/PX-220/FB88# system, the modified kenaf fiber still acted as main reinforcing material, and the amount of it was constantly the the optimal. PX-220 and FB88# compoundly flame retarded kenaf reinforced poly (lactic acid) composites, and the results showed that:the combination of PX-220 and FB88# improved the heat resistance of the composites; the tensile strength of the composites increased by the addition of FB88#; the PX-220/FB88# flame retardant system could effectively resist droplet, with significant charring.Kenaf was first modified by zinc acetate dihydrate so that the surface of which was coated with a layer of ZnO particles, then RDP was adsorped onto the ZnO coated kenaf in situ. The RDP/ZnO/kenaf ternary self-assemble system was prepared by the way above.The ternary self-assemble system was solution mixed and melt blended with poly (lactic acid) in turn. It was found that:mechanical properties of composites were linear rising with the increase of the addition amount of kenaf; RDP not only improved the compatibility of kenaf and poly (lactic acid) matrix, but also dramatically enhanced the flame retardancy of the composites; ZnO catalyzed the combustion of the composites to charing and played a "bridge" role between RDP and kenaf.