Process factors and performances of recycled plastic-wood fiber composites.

The influence of the process factors on the physical properties of recycled wood-plastic composite panels was investigated. Three recycled plastics (polystyrene, polyethylene, and polypropylene) and poplar (Populus sp.) fiber were used as the main raw material, and the various process factors such as different kinds of plastics, the mixing ratio between the wood material and its plastic counterpart and hot-pressing temperature were examined. The results show that in terms of desirable properties the preferential order of three plastics is polystyrene, polypropylene and in last place, polyethylene. The mixing ratio between wood and plastics has its best performance at 50/50 wood-plastics ratio. Properties of tensile strength and IB decrease when the wood-plastics ratio is lower and properties of MOR and MOE are weakened when it becomes higher.A hot-pressing temperature of 190℃ is the best among three levels of temperature. MOR, MOE, tensile strength and IB decrease when temperatures are lower. At extremely high temperature the wood fiber material degrades drastically and starts to seep out.Based on both of the maximum difference analysis and the variance analysis, significance test shows the optimum conditions for recycled plastics/composites to be polystyrene,a wood-plastic ratio of 50/50 and a hot_pressing temperature of 190℃.