Study On The Preparation And Accelerated Ageing Properties Of Wood Flour/High-density Polyethylene Composites

As a kind of new environmental friendly material, WPC has both the characteristics of wood and plastics. The development and application of WPC has important significance as the substitute material of wood, and also for the recycling of Waste plastics. In this paper, modifying conditions was studied while KH550 as a coupling agent, composites were prepared to research the effect of formulation and processing technology on the properties. Effect of wood flour content, compatibilizer, Anti-aging agent and release agent on the ageing performance of composites was mainly studied. Conclusions are as follows:(1) Orthogonal test was carried out to determine the optimum modifying conditions by the viscosity of WF/liquid paraffin. The result is KH550 2%, modifying time 100min, modifying temperature 80℃. The result of 60h moisture regain and FTIR indicated that hydrophobic modification of wood fiber was effective.(2) Wood fiber improved the impact strength obviously, and compatibilizer EVA increased the tensile strength of composites, release agent ZnSt improved the processing performance and external quality, while nano-TiO₂ fully improved the mechanical properties of composites. The best Hot-pressing process is pressing temperature 160℃, pressing time 14 min.(3) By using the index of mass loss, mechanical properties, color and carbonyl index, the effect of wood flour, ZnSt, EVA and nano-TiO₂ on the ultraviolet aging performance was discussed. Wood fiber increased the content of free radical, so that the ageing of composites was promoted. ZnSt accelerated the ageing performance to some extent, however, proper addition would be acceptable. EVA played a negative role in the anti-ageing of composites, due to the ester carbonyl groups inside. Rutile type nano-TiO₂ obviously improved the anti-ageing properties of composites.