| Wood/plastic composite is a new material compounded by wood and plastics in definite technology. There are already several kinds of products produced by different technology. More and more wood/plastic composite products are being widely used. Wood/plastic composites become the focus of wood and plastics utilization and research all over the world. Using recycled plastics and wood materials to make wood/plastic composites is a very effective approach to reuse the discards and lessen the pollution of them to the environment. The main obstacles in the reuse of discard plastics are: The sorting of recycled plastics needs a great deal of work and the costs of that are high. With a view to resolve the above two problems, the blend of liner low density polyethylene (LLDPE) which is usually used to make film and polystyrene (PS) which is usually used to make foaming and injection products were used to preparing wood/plastic composites. LLDPE, PP and PS, the main plastics in plastic industry, were chosen as the raw materials. The relativity between property of plastics and that of wood/plastic composites would be evaluated and the necessary of blend of LLDPE and PS would be advised. The LLDPE/PS alloys were prepared through polymer blend and the effects of different proportion of blend and blend temperature on the properties of the alloys were investigated. Through the blend of LLDPE and PS to improve some properties of theplastics and the properties of the composites which can meet the need of products are hoped also. The effects of LLDPE/PS alloys in different proportion and blend temperature on the properties of plastic alloy/woodfiber composites were studied and the property relativity between plastic alloy and their wood fiber composites were discussed also. The research results indicated:Different plastics had different properties, and the properties of their wood/plastic composites were different also. There was obvious relativity between the properties of plastics and their wood/plastic composites. LLDPE was a flexible and tough polymer; the compounding property of LLDPE with woodfiber (WF) was the best. The impact-resistant property of LLDPE/WF composites was good, but the flexural strength and modulus was very low. Polystyrene (PS) as a rigid and brittle material, the flexural strength and modulus of its WF composite was very high. But the impact strength was very low and the compounding property of wood fiber with PS was not good. These were the reasons why PS or LLDPE/woodfiber composites can't be widely used in practice till now. Because PP was not only rigid but also tough, and the general properties of PP/WF composites were the best, so it was being widely used in practice. Through above comparing, the conclusion is formed that it is very necessary to develop the research on the blend of LLDPE and PS. Combining the mechanical properties and processing properties of the two plastics, the wood/plastic composites with better general properties are hoped to obtained. The results of LLDPE and PS blend indicated that the effects of LLDPE/PS proportion and blend temperature on the mechanical properties were significant. The effect of blend proportion on the properties of alloys was greater than those of blend temperature. With the increase of the LLDPE content in plastic alloys, the impact strength of the alloys increased, but the flexural strength, flexural modulus and tensile strength all decreased. The effects of blend temperature on the properties of alloys for different blend proportion were different. The analysis of differential scanning calorimetry (DSC) and dynamic mechanical analyze (DMA) told us that the Tg of each plastic in alloys had not closed up which indicated that the miscibility of the two plastics is bad, but the degrading temperature was changed. The properties of LLDPE/PS alloy/woodfiber composites were not onlycorrelation to the properties of plastics used in alloy but also relative to the blend proportion. The properties of alloy/woodfiber compos...
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