Study On The Properties Of The Extruded Straw And High-density Polyethylene Composites

High-density polyethylene(HDPE) and agricultural straw were used as the main raw materials to prepare straw/HDPE composites by melt extrusion.The maleic anhydride grafted polyethylene(MAPE),maleic anhydride grafted polypropylene(MAPP) and titanate(TSZ) were utilized to modify the composites,and the influence of coupling agent type and content on the mechanical properties were studied.Using one-way ANOVA to analyze the significant influence of the coupling agents on mechanical properties of composites,and then screen out the coupling agent with better modified effect.In order to understand the mechanism of the wood-plastic composites modification,the dynamic mechanical thermal analyzer(DMA), scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS) were used to research the composites with better modified effect.The results can be shown as follows:(1) Coupling agents can improve the interfacial bonding of the composites,different types of coupling agents play the different roles.Maleic anhydride type coupling agents can effectively enhance the bonding force between the two phases.(2) Different types of maleic anhydride-type coupling agents have different effectiveness on improving interfacial bonding;MAPE can improve the mechanical properties of the composites better than MAPP.TSZ in the composites would inhibit the interfacial bonding and reduce the mechanical properties,but it would improve the rheology property,which in turn enhance the extruding speed and improve the surface quality.However,adding the mixture of MAPE and MAPP in the composites is no better than single MAPE.(3) The straw content brought some varying degree effect on mechanical properties of composites.With increasing the straw content,the impact strength of composites decreased and the flexural properties,impact strength increased.(4) One-way ANOVA showed that the straw contents,MAPE contents,MAPP contents, TSZ contents have a very significant influence on the every mechanical properties of composites.(5) DMA analysis showed that by adding MAPE in the composites,the storage modulus and glass transition temperature increased,whereas the damping performance decreased;when the straw contents increased,the storage modulus increased,and the loss angle tangent decreased significantly.SEM observation showed that the composites without MAPE have a clear separation of straw and HDPE,after adding MAPE the interfacial bonding of the composites significantly improved and the surface of impact fracture surface appeared obvious"drawing".XPS analysis showed that the esterification occured between some coupling agents and straw,C_1s peak area increased and the electronic bonding energy enhanced.