| Polyether ether ketone(PEEK)resin is a comprehensive high performance of semi-crystalline engineering plastics,which has high temperature,corrosion resistance,fatigue resistance,high mechanical strength and other excellent performance.PEEK possesses well fluidity and is easy to process,so it is widely used in automotive,aerospace and other transportation,IT industry,machinery and medical and health fields.PEEK resin has good wear resistance and it is considered to be the ideal polymer wear-resistant materials.With the development of society and industry progress,the requirements of friction materials are getting higher and higher.As a single PEEK is unable to fully meet the needs of the material wear resistance of the requirements,other materials are usually doped in PEEK to reduce its friction coefficient and wear rate,to show a more excellent wear resistance,to broaden its scope of application in the field of friction.In order to improve the wear resistance of PEEK and realize its high performance,zinc oxide nanoparticles(ZnO)were used as reinforcing materials.To solve the problem of nanoparticles agglomeration,we modified nanoparticles surface with silane coupling agent in this experiment and received modification of ZnO nanoparticles(m-ZnO).After that,we respectively prepared PEEK nanocomposites adding ZnO and m-ZnO via melting blend and studied the influence of the nanoparticles content on mechanics performance,thermal stability,crystallization melting behavior and friction and wear performance of composite materials.FTIR spectra confirmed that the coupling agent was successfully grafted to the surface of ZnO.The experiment results showed that the addition of nanoparticles improved the thermal decomposition temperature and the mechanical properties of the composites,but increment was small.After joining m-ZnO nanoparticles,nanoparticles were better dispersed in the resin and reduced the particles agglomeration,so the PEEK/ZnO composites thermal stability,mechanical properties and wear resistance were superior to PEEK/ZnO composites.When the content of m-ZnO was 5wt%,its friction coefficient and wear rate of materials were the lowest and respectivelyreduced by 9.3% and 25.0% compared with the pure PEEK.Microstructure analysis with scanning electron microscopy(SEM)on the friction and wear surface showed that the furrows of the composites became shallow and the surface became flat after introduction of the nanoparticles.The above confirmed that the addition of nanoparticles improved the wear resistance of the matrix resin.Short carbon fibers(SCFs)were added in the above m-ZnO/PEEK nanocomposites in order to further improve the mechanical properties and friction and wear performance of composite materials.Polyether sulfone(PES)was used to physically wrap SCFs in order to improve the interfacial adhesion and enhance the compatibility between carbon fiber and resin matrix.The case of carbon fiber surface coated and the degree of dispersion in the matrix were characterized by SEM,the results showed that the PES had coated on the carbon fiber surface and coated carbon fiber were well dispersed in the matrix.The influence of the m-ZnO and w-SCF(wrapped carbon fiber)content on the properties of composite materials was studied.The experimental results showed that the mechanics performance of composite materials added carbon fiber was significantly improved and the maximum tensile strength and bending strength respectively increased by 40% and 37.7% compared to pure PEEK.Among all of composite material which had been prepared,the wear resistance of 5wt%m-ZnO/10wt%w-SCF/PEEK composites was the best,the friction coefficient and wear rate were reduced by 35.3% and 72% respectively.As a result,the nanocomposites of adding carbon fiber achieved the optimal performance optimization,improved the mechanical properties,friction and wear properties of the materias,as well as thermal stability. |
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