Study On Preparation And Properties Of PTFE Self-lubricating And Wear-resistant Composites

The Polytetrafluoroethylene(PTFE)has been widely used,due to its resistant corrosion,high temperature resistance,low coefficient friction and good insulativity characteristics.However,its drawbacks including poor mechanical properties,poor creep resistance,molding and secondary processing difficulties,abrasion resistance and poor thermal conductivity limit its wider application.The wear resistance of PTFE is usually improved by fiber,while the fiber will always increase the friction coefficient of the composites.For the disadvantage of PTFE/GF composites,that it has bigger friction coefficient,this paper has explored the influence of PHB on the mechanical and tribological properties of PTFE/GF composites.And on this basis,adding nano-Cu particles,it explored the relationship between microstructure and wear performance of the PTFE/GF/PHB/nano-Cu composites.This article further investigated nucleating agent,nano-Cu and those two composites modified mechanical and tribological properties of PTFE/GF composites respectively.The main research contents and results are as follows:(1)After adding PHB,the hardness of PTFE/GF/PHB composites increased,tensile strength and the friction coefficient decreased,spring rate had no obvious changes.When the content of PHB was 6%,the mechanical and tribological properties of PTFE/GF composites were totally the best.Shore D hardness was 63,tensile strength was 13.94MPa,rebound rate was 90%,the friction coefficient was reduced to 0.1746 and wear rate was 6.84×10-6(mm3/N·m).The worn surface SEM photographs showed that the furrows of the wear surface became thin and shallow;the degree of abrasive wear was also reduced.The transfer film distribution of the PTFE/GF/6%PHB composites was more complete comparing with the transfer film of the PTFE/GF composites.However,there were still small scratches on the transfer film.(2)After adding nano-Cu,the wear rate of the PTFE/GF/6%PHB/nano-Cu composites was firstly decreased and then increased slightly,the friction coefficient increased slightly;when the nano-Cu content was 0.3%,the wear rate of the composites was lowered to 1.60×10-6(mm3/N·m).The worn surface of PTFE/GF/6%PHB/0.3%nano-Cu composites showed more smooth comparing with the PTFE/GF/6%PHB composites,it showed very slight abrasive wear and abrasive resistance was much better.The compact and stable transfer film of the PTFE/GF/6%PHB/0.3%nano-Cu composites were produced on the metal couplings surface,which showed more uniform and complete.(3)After adding the nucleating agent,the friction coefficient and the wear rate of the PTFE/GF/NA composites were both decreased;after adding nano-Cu,the wear rate of the PTFE/GF/nano-Cu composites was also decreased;the friction and wear properties of the PTFE/GF composites can be synergistic modified by filling 0.5%nucleating agent and 0.3%nano-Cu.The abrasive wear of the PTFE/GF/0.3%nano-Cu composites was greatly improved;the depth and width of the furrows were both decreased.When 0.5%nucleating agent and 0.3%nano-Cu were filled into composites in the same time,only minor scratches existed on the wear surface,and it showed very slight abrasive wear.The transfer film of the PTFE/GF/0.5%NA/0.3%nano-Cu composites showed more uniform and dense comparing with the PTFE/GF/0.5%NA composites,which indicated that the friction and wear properties of the PTFE/GF/0.5%NA/0.3%nano-Cu composites would be integrated to improve.