Interfacial Modulation And Properties Study Of Carbon Fiber Fabric Reinforced Poly(ether Ether Ketone)composites

Carbon fiber fabric（CFF）reinforced poly（ether ether ketone）（PEEK）composites stand out in the field of carbon fiber（CF）reinforced high performance thermoplastic resin composites due to many advantages such as high strength,high modulus,high impact resistance,chemical resistance,low density and good fatigue resistance.However,the defects such as low surface activity and low surface energy of CFF as well as high viscosity of PEEK resin matrix in molten state,which are not conducive to good infiltration of carbon fibers,cause weak interfacial bonding between CFF and PEEK resin matrix,and the improvement of mechanical and tribological properties of the composites is limited.In order to improve the interfacial bonding of carbon fiber fabric/poly（ether ether ketone）composites,this paper firstly optimized the preparation process of CFF/PEEK composites,and then treated the carbon fiber fabric with homemade poly（ether ketone ketone）（PEKK）aqueous sizing agent and graphene oxide-poly（ether ketone ketone）（GO-PEKK）composite sizing agent respectively,and analyzed the effect of sizing agent on the interfacial bonding of the composites mainly by examining the surface properties of carbon fibers,mechanical and tribological properties of the composites.The main studies and conclusions are as follows:（1）CFF/PEEK composites were prepared by the thin film lamination,powder impregnation and slurry methods.Since the CFF/PEEK composites were prepared by the slurry method,the PEEK resin matrix was introduced into the CFF with the aid of anhydrous ethanol/deionized water solvent mixture,and the resin matrix was more easily immersed into the fiber bundles with the aid of the solvent mixture,which reduced the melt resin infiltration distance and facilitated the interfacial bonding between the fibers and the resin matrix,so the mechanical and tribological properties of the CFF/PEEK composites prepared by the slurry method were better than those of the other two methods.The mechanical properties include interlaminar shear strength,flexural strength,flexural modulus,and impact strength of53.3MPa,481.9MPa,19.4GPa,and 87.7KJ/m²,respectively.Tribological properties include average coefficient of friction and wear rate of 0.38μand 14.49×10^-4m³N^-1m^-1,respectively.In addition,the CFF/PEEK composites prepared by the slurry method also had the best heat resistance with an initial decomposition temperature(T_5%)of 591°C.（2）The initial decomposition temperature of PEKK aqueous sizing agent is 603°C,which is much higher than the composite molding temperature.The surface activity and roughness of PEKK aqueous sizing CFF（PEKK-CFF）are enhanced,which is beneficial to the improvement of fiber surface energy,of which 5wt%PEKK-CFF surface energy is the largest.The effect of PEKK aqueous sizing agent on the interfacial properties of CFF/PEEK composites was investigated,and the interfacial properties of PEKK-CFF/PEEK composites were improved because PEKK not only improved the surface energy of carbon fibers,but also had good compatibility with the PEEK resin matrix.The 5wt%PEKK-CFF/PEEK composite has the best mechanical and tribological properties relative to the CFF/PEEK composite.The mechanical properties of the 5wt%PEKK-CFF/PEEK composites including interlaminar shear strength,flexural strength,flexural modulus and impact strength were improved by35.6%,29.9%,33.5%and 24.5%,respectively.The tribological properties of the 5wt%PEKK-CFF/PEEK composites included a 10.5%and 15.9%reduction in the average coefficient of friction and wear rate,respectively.The initial decomposition temperature of5wt%PEKK-CFF/PEEK composites was also elevated to 598°C compared to CFF/PEEK composites.（3）Based on the above research and test results,GO was dispersed into PEKK aqueous sizing agent to prepare GO-PEKK composite sizing agent,while GO-PEKK composite sizing CFF（GO-PEKK-CFF）was used afterwards,and finally GO-PEKK-CFF/PEEK composite was prepared by slurry method.The initial decomposition temperature of the GO-PEKK composite sizing agent is 588°C,which is higher than the molding temperature of the CFF/PEEK composite.The surface activity and roughness of GO-PEKK-CFF were increased relative to CFF,which contributed to the improvement of fiber surface wettability,with0.5wt%GO-PEKK-CFF surface energy exhibiting the maximum value.In addition to the reinforcing effect of PEKK,the interfacial properties of the composites were further improved because the introduction of GO further improved the surface energy of carbon fibers and GO provided mechanical locking interaction for the composites.0.5wt%GO-PEKK-CFF/PEEK composites showed the greatest improvement in mechanical and tribological properties compared to CFF/PEEK composites.Among them,the mechanical properties including interlaminar shear strength,flexural strength,flexural modulus and impact strength were improved by 57.4%,36.4%,54.6%and 60.7%,respectively.The tribological properties of0.5wt%GO-PEKK-CFF/PEEK composites including average coefficient of friction and wear rate were reduced by 26.3%and 37.6%,respectively.The initial decomposition temperature of the 0.5wt%GO-PEKK-CFF/PEEK composites was also increased to 593°C relative to the CFF/PEEK composites.In summary,all the above three methods effectively improved the interfacial bond strength of CFF/PEEK composites,and the mechanical and tribological properties of the composites were also improved.This has a positive effect on optimizing the interfacial bond strength and the corresponding mechanical and tribological properties of carbon fiber reinforced thermoplastic resin matrix composites.