An Environmentally Friendly Recycled-Polyethylene Composite Reinforced by Diatomaceous Earth and Wood Fiber

Abstract

This study aims to develop a new wood-plastic composite (WPC) material from recycled thermoplasctics. The recycled low-density polyethylene (rLDPE) and high-density polyethylene (rHDPE) were used as matrix, whereas the diatomaceous earth waste (D) and wood fiber (WF) as filler. Recycled-LDPE and rHDPE were recovered and pelletized by a plastic recycling process. The 10-30wt.% diatomaceous earth waste was heat-treated at 200°C to remove impurities. The diatomaceous earth, maleic anhydride grafted polyethylene (MAPE), CaCO3, slip agent, antioxidants and WF were then mixed at 160°C, for 10 minutes, at stirring speed 50 rpm to produce wood-plastic composite material. The mechanical strength and thermal properties of the composites were investigated. The composite containing D and rLDPE results in an increase the hardness of the material which is higher than that of the virgin-LDPE. The tensile and impact strengths of the composite material prepared by rLDPE and D were higher than those of the rHDPE composite material. It is found that LDPE has excellent fluidity, which is helpful for subsequent processing. In addition, the diatomaceous earth waste can be used to reduce the cost of the raw material, and the product has both effects of environmental protection and marketability.