Preparation、Properties And Application Of Thermoplastic Elastomer Based Wood-plastic Composites

To solve the problems of oil resource depletion and white pollution of plastic materials,it is an urgent problem to develop new environmental protection composite materials with excellent performance and degradability.Polyurethane is a kind of engineering plastic material with excellent properties and wide application.Thermoplastic polyurethane elastomer(TPU)develops rapidly but is difficult to degrade.The addition of natural plant fibers to TPU plastic materials to synthesize environmentally friendly TPU based wood plastic composites(WPC)is of great significance.Firstly,the technological conditions for the synthesis of pure TPU substrates were studied.Using isophorone diisocyanate(IPDI)and diphenylmethane diisocyanate(MDI)as raw materials to synthesize pure TPU substrates,and the effects of different polyols and chain extender on TPU properties were investigated.Excellent TPU synthesis process conditions.The experimental results show that the TPU synthesized with IPDI as raw material has better crystallization performance.The molar ratio of raw material is PTMG1000:IPDI:BDO 1:3:2,the prepolymerization reaction temperature is 60℃,the prepolymerization reaction time is 2hour、 the maturation temperature is 90℃,and the maturation time is 48 hour.The results show that IPDI linear thermoplastic polyurethane produced by the reaction with PTMG is the target product.The TPU SEM photos show that the synthesized product has the structure characteristic of microphase separation.The TG results show that initial decomposition temperature of 270℃.Then,TPU based wood plastic composites were prepared by adding bamboo powder and wood powder(WF)two fillers in the TPU synthesis process.The effects of bamboo powder or wood powder content,acetylated modified wood powder(AWF)content,coupling agent addition amount and WF particle size on WPC properties were investigated.The results showed that: filling appropriate amount of bamboo powder and wood powder can enhance TPU,and wood powder enhancement effect is better,with the increase of wood powder filler content,the tensile strength increased first and then decreased,when the wood powder content was 15 wt%,the maximum tensile strength of the composite was 7.16 MPa;through the study found that different WF particle size on the properties of the WPC,found WPC tensile strength :100 mesh >200 mesh >325 mesh >400 mesh,elongation at break:100mesh >400 mesh >325 mesh >200 mesh were selected;the AWF structure after acetylation modification was more regular and the enhancement effect was better;the tensile strength TPU up to 11.24 MPa.when filling 20 mesh WPC Shao A hardness increased with the addition amount.Lastly,the WPC 3D printing wires were prepared,and the extrusion and printing properties WPC different WF contents were investigated.The extrusion wire printing performance is better for 5wt% and 10wt%.