Preparation And Properties Of Poly Ether Ether Ketone/Carbon Nanotubes Composites

In the past two years,our team has been focus on the preparation and investigation on the properties of Polyether Ether Ketone(PEEK)Composites,PEEK is a kind of special engineering plastic with good comprehensive performance,but the electrical and friction performance are much poor.Multi-walled Carbon Nanotubes(MWCNTs)were doped into Polyether ether ketone,PEEK/MWCNTs composites were prepared by hot forming and injection molding.The mechanical properties,electrical properties,DSC,TGA,DMAand IR of PEEK/MWCNTs composites were analyzed,and the effects of heat treatment on the mechanical and thermal properties of PEEK/MWCNTs were investigated.The results achieved are shown as follows:For the method of molding,the composite material prepared by injection molding has better performance and is more easily industrialized,which has a wider range of applications.The PEEK/MWCNTs composites prepared by injection molding have higher mechanical properties compared with pure PEEK.Among them,the mechanics of MWCNTs-COOH composites are the best,its tensile strength,bending strength and impact strength are measured up to 101.09 MPa,280.65 MPa and 10.6 KJ/m2.With the increase of MWCNTs content,the surface resistance of PEEK/MWCNTs composites prepared by injection molding decreases,when the content of MWCNTs is 4%,the surface resistance of PEEK/MWCNTs-OH composites is 3.21 × 109 Ω,which can be used in the field of antistatic materials.The surface resistance value of PEEK/MWCNTs-COOH composite is 2.07 × 105 Ω,which can be used in the field of conductive materials.Wear capacity and friction coefficient of PEEK decrease with the doping of MWCNTS,and the loading capacity increases by more than once.When the doping content of MWCNTs is 4%,the wear capacity decreases up to 0.6 mg,and the carrying capacity increases from 800N to 1600N.The doping of MWCNTs has an effect on the crystallization process and grain growth of PEEK,MWCNTs can promote the crystallization of PEEK,which is favorable for the melting temperature,thus the melting point is enhanced.The dynamic mechanical properties of PEEK/MWCNTs are investigated.It is found that the storage modulus and tans of composite materials are improved when the doping content of MWCNTs increase.And as the frequency increases,the storage modulus increases but the tanδ decreases.The optimum heat treating time is 2 h and the optimum temperature is 250℃.The tensile strength and flexural strength of the composites are improved to 95.04 MPa,which is 9.2%higher than that of the untreated composites,and the flexural strength is up to 265.88 MPa,which is 18.6%higher than that of untreated composites.The melting point and crystallinity of composite materials can be enhanced significantly by heat treatment.the melting point of the composites increases to 348.13℃ when the heating temperature is 250℃,the melting point of the composites is 4.46℃ higher than that of the untreated composites,and the crystallinity rises to 31.5%,which is 4.88%higher than that of untreated composites.The storage modulus of composite material can be improved significantly by heat treatment,which can expand the use of composite materials.