Water Absorption and Effect of PP/WPC

Polypropylene(PP)/wood flour composites(WPC)were prepared by extrusion.The influence of immersion time,the compatibilizer(maleated polypropylene)and silane coupling agent on water absorption of WPC was studied.The effect of the water absorption on flexural strength,expansion of water absorption and the oxidation induction time(OIT)was also studied.The results showed that with increasing immersion time,the water absorption of WPC increased rapidly within the first 30 days and stopped increasing thereafter.Both the silane coupling agent and the compatibilizer reduced the water absorption of WPC,however,the silane coupling agent only reduced the initial absorption percentage,while the compatibilizer reduced the initial absorption percentage,as well as the saturated absorption percentage.The flexural strength of WPC reduced rapidly with increasing the absorption percentage and then tended to become stable after the WPC saturated with water.Both the silane coupling agent and the compatibilizer could improve the strength of WPC,while the compatibilizer can achieve the improvement to a greater extent.The OIT of WPC decreased with increasing the immersion time.