Preparation And Properties Of Carbon Fiber/Nano-TiO₂/Poly （Ether Ether Ketone） Wear-resistant Composites

The wear-resistant material is indispensable in the industry and life. With the promotion of the requirements, the resin wear-resistant material with its unique advantages such as light, self-lubricated, easy-processing etc. is booming. Poly ether ether ketone has the properties of high mechanical strength, chemical stability, abrasion resistance and easy processability. As a typical thermoplastic high performance polymer, PEEK has been widely used in military and civil fields. PEEK is a good wear-resistant polymer material and can keep a good abrasion resistance in the range of load, sliding velocity, temperature. However, on the one hand, PEEK has a high coefficient of friction and on the other hand the requirement of anti-wear material is more and more strict. As a result, it is very important and necessary to make the modification.The carbon fiber is effective to improve the friction and wear properties of polymeric material. Researchers always used PAN-based carbon fiber to modify polymer. We modified PEEK by using micron grade isotropic pitch based short carbon fiber（SCF）, which can not only reduce the friction coefficient and wear rate but also has an advantage on the cost. Nanoparticles modified polymer materials has attracted more and more attention because of its unique modification effect. We introduced nano-TiO₂ to the composite system and investigated the friction and wear properties of ternary composites. First, the SCF/PEEK、TiO₂/PEEK were prepared by melt blending and chose the best filling ratio range. Then the SCF/TiO₂/PEEK composites were prepared. The research showed that SCF had a good synergistic effect with TiO₂ in a certain range and SCF/TiO₂/PEEK had a better wear-resistance than SCF/PEEK or TiO₂/PEEK under different friction conditions especially in the severe condition. During the friction process, the deciduous TiO₂ could concentrate around the SCF and protect the SCF temporarily to alleviate the further damage of the SCF, which made the SCF hard to pull out from the matrix and reduced the degree of the interface debonding. In addition, the nanoparticles acted as the roller between the two matching surfaces which provided the rolling friction and reduced the friction shear stress, friction coefficient and surface contact temperature. What’s more, SCF/TiO₂/PEEK had a higher hardness, thermal stability and made up the negative effect of crystallization caused by TiO₂.For polymer based composites, the performance of the materials is mainly affected by the degree of filler dispersion and the interaction between the interfaces. Therefore, we used polyetherimide（PEI） which has a good compatibility and a similar processing temperature with PEEK to wrap SCF in order to improve the dispersion of SCF and the interface bonding with the matrix. At the same time, the coupling agent KH570 was used to modify nano-TiO₂, which was effectively reduce the agglomeration. Three series of composites f-SCF/PEEK, m-TiO₂/PEEK and f-SCF/m-TiO₂/PEEK were prepared. The results indicated that the wear resistance and thermal stability of f-SCF/m-TiO₂/PEEK was further improved compared with SCF/TiO₂/PEEK, which is beneficial to meet the higher requirements.