Study On Preparation And Properties Of WSP/PP Composites

Polypropylene (PP) is an important polyolefin material, which is used in many fileds such as industry, agriculture and everyday life due to its excellent properties. In past decade, the development and application of PP based composites incorporating with biomass fibers have attracted a great deal of attention from public, because this kind of composites have good melting process, imitation-wood optical effects and environment friendship, and has been applied in construction, automobile, daily goods and so on. Especially, non-wood biomass raw materials attract more and more interesting with the scarcity of forest. Walnut shell, a litter of forestry industry, is used as filler of polymer based composites due to its natures liking wood fiber, which contains cellulose, lignin and hemicellulose.The polymer based composites were prepared with PP as matrix and walnut shell powder (WSP) as filler. It was investigated how the filler size and surface modification with alkali on WSP affected the properties of WSP/PP composites. The interfacial compatibilizer like maleic anhydride grafted PP copolymer (PP-g-MAH) and elastomers like ethylene-vinyl acetate (EVA) and ethylene-propylene-diene monomer (EPDM) were blended into composites. in order to improve the interfacial compatibility between matrix and filler and enhance the impact resistence. The thermal stability and degradation behaviors of WSP/PP composites were studied preliminarily.The distribution of particle size and content of WSP have significant effect on the mechanics of WSP/PP composites:the mechanical strength of composites decreases with the filler loading increasing. The properties of composites has no obvious improvement after surface modification with alkali, but the tensile and flexible strength of WSP/PP composites are enhanced after blending with PP-g-MAH. For example, the tensile and flexible strength of PP based composites incorporating with50wt%WSP and7wt%PP-g-MAH both increase32%. comparing with that of WSP/PP composites without interfacial compatibilizer. Elastomer can toughen composites and weaken their rigidness. and EPDM has more effect than EVA. The thermal stability of composites will be destroyed with blending WSP. and enhanced by PP-g-MAH. The effect of EPDM on the thermal stability is negligible.The study on the preparation and interfacial property of WSP/PP composite will lay the theorical and experimental groundwork for development and application of biocomposites incorporating with WSP. It has enormous social benefit and economic outlook on relieving forestry lack, advancing the utilization of recycling biomass raws, and protecting environment.