Use of Magnesium Hydroxide as Flame Retardant in Poly(Lactic Acid)/High Impact Polystyrene/Wood Flour Composites

This work aimed to use magnesium hydroxide (MH) as a flame retardant in poly(lactic acid) (PLA)/high impact polystyrene (HIPS)/wood flour (WF) composite. The 80/20/20 PLA/HIPS/WF composite was melt mixed with three loadings (20, 30 and 40 phr) of MH on a twin screw extruder, followed by an injection molding. The prepared wood-plastic composites (WPCs) were investigated for their impact strength (IS), tensile strength (TS), Young’s modulus (E), elongation at break (EB), flammability and morphology. The results showed that the 80/20/20 PLA/HIPS/WF composite exhibited higher IS, TS and E than the neat PLA, but at the expense of reducing the EB. It was also found that the WPCs filled with MH at all loadings provided much higher flame resistance and E over the neat PLA, HIPS, PLA/HIPS blend and PLA/HIPS/WF composite. Therefore, the MH could play an effective role as flame retardant in the WPCs.