Study On The Preparation And Properties Of PVC Wood-plastic Composites

Wood-plastic Composites (WPC) are manufactured by wood fiber and thermoplastics,it can solve the “White Pollution” problem, but also can improve the utilization ofagricultural and forestry waste, turning waste into treasure, get high value-added industrialproducts. WPC is a new material with the advantages of both wood and plastics, therefore,the composites has vast potentials for development and considerable market prospects. Thisstudy take sawdust and PVC as primary materials, then these materials are mixed in doubleroller mixer and molded by flat-press process. The effect of wood species, particle size,wood flour content, processing agent and process conditions on the mechanical propertiesof WPC was discussed.These results indicate that: The influence of mechanical properties caused by woodspecies is not obvious. It is mainly due to the similar chemical composition of the pine andpoplar. Mechanical properties can not be enhanced when the particle size of wood flour istoo large or too small with the same wood flour content. When the wood flour particle sizewas60-80mesh, the comprehensive mechanical properties of composites is better. Theresults show that the tensile strength and impact strength of the composites decreasedsharply with the increase of wood flour content. Flexural strength is just the opposite. Theinterfacial compatibility and the mechanical properties of WPC were improved by addingcoupling agent. The modified effect of the titanate coupling agent was better than the Vinyltriethoxy silane coupling agent, when the content of the coupling agent achieved3%wt,impact strength, tensile strength and flexural strength of the composite were better. Theimpact strength can be obviously enhanced by adding CPE, when thermoplastic elastomer(CPE) is added into PVC, the toughness of the composites is improved, the impact strengthhave multiplied. Plasticizer DOP can significantly improve the Melt flow properties of thecomposite, improve the processing performance, it can also shorten the time of milling.Because of PVC has a narrow processing temperature range, when the temperatures are at140℃,160℃,180℃, we studied the effect of processing temperature on the properties ofthe composite, at160℃,wood-plastic composites have excellent comprehensive mechanicalproperties.