Synergistic influence of halogenated flame retardants and nanoclay on flame performance of high density polyethylene and wood flour composites

Abstract

High density polyethylene and wood flour (HDPE/WF) composites containing three flame modifiers (FMs) (i.e., two fire retardants: 1,2-bis(pentabromophenyl) and ethylene bis(tetrabromophthalimide), and one nanoclay), maleic anhydride grafted polyethylene (MAPE) and other processing aids were prepared through twin-screw extrusion, and their properties were characterized. The addition of FMs lowered the composite strength, but composite modulus did not change in a systematic manner. The fiber-polymer interfacial adhesion became increasingly deteriorated with the FM addition, and the use of MAPE coupling agent in the composites helped improve the interfacial adhesion. There was a synergistic effect of the fire retardants, nanoclay and MA-g-PE, especially for 1,2-bis(pentabromophenyl)–clay–MAPE system, on thermal stability and fire retardancy with lowered heat release rate and total heat release of the composites, leading to significantly improved flame performance.