PA6 Phosphorylation To Prepare Water-based Sizing Agent For Thermoplastic Carbon Fiber Composite Materials

Sizing treatment of carbon fibers with a sizing agent can significantly improve the wetting characteristics of the carbon fiber surface,increase the content of active elements on the surface of the carbon fiber,increase the wettability between the fiber and the matrix resin,and increase the interface binding performance between the fiber and the matrix resin,thereby improving the carbon fiber composite Interlaminar shear strength and overall mechanical properties.In this paper,the phosphorylation modification process of polycaprolactam resin(PA6)was studied,and the phosphorylated PA6 water-based resin was prepared.The structure of the modified product was characterized by infrared and nuclear magnetic resonance spectroscopy.The properties of surface tension and thermodynamic stability were analyzed.Taking the acid value and viscosity of the modified product as control parameters,the optimal process route of the reaction synthesis was discussed:m(PA6): m(8102P)= 1: 1.5,the reaction time was 4h,and the reaction temperature was 210 ℃.Experimental data show that the modified product has excellent high temperature resistance,uniform particle size distribution in aqueous solution,and good stability.When the emulsion concentration is 1%,the surface tension of the emulsion is at least 22.5 m N · m-1,which has excellent surface activity.8102PPAK sizing agent was used to sizing the carbon fiber.When the sizing agent emulsion concentration was 1%,the minimum contact angle between the surface of the carbon fiber and water was 51.25 °.The monofilament tensile strength increased by 18.12%.When the sizing agent application amount was 4 mg / g,the slurry film on the surface of the carbon fiber was dense and uniform,and the dispersion coefficient β of the carbon fiber in the nylon resin was 0.87.Graphene oxide was uniformly dispersed in 8102 PPAK,and a graphene oxide-reinforced water-based PA6 based thermoplastic sizing agent(GO-8102 PPAK type)was successfully prepared.The carbon fiber was sizing treated.The effect of the amount of graphene oxide on the properties of carbon fiber was studied.The results show that when the amount of graphene oxide added is 0.06%,the tensile strength of the monofilament of the carbon fiber reaches a maximum of 4.87 GPa,and the minimum contact angle of the carbon fiber with water is 49.01 °.The content of oxygen on the surface of the carbon fiber increased by 4.67% compared with the carbon fiber treated with 8102 PPAK sizing agent,indicating that the carbon fibertreated with GO-8102 PPAK sizing had good surface activity.Finally,the sizing carbon fiber was woven into a carbon fiber plain weave,and the CF / PA6 composite was prepared by the compression molding method.The effect of the sizing agent on the mechanical properties of the thermoplastic composite was studied.The results show that: CF / PA6 composites made of carbon fiber treated with8102 PPAK sizing agent have tensile strength,flexural strength,and interlaminar shear strength increased by 77.93% and 48.55 respectively compared with CF / PA6 composites made of unsized carbon fiber.%,54.79%;The tensile strength,flexural strength,and interlaminar shear strength of CF / PA6 composites treated with GO-8102 PPAK sizing agent were increased by 98.46% compared to CF / PA6 composites prepared from unsizing carbon fibers.65.04%,73.69%;It shows that CF /PA6 composites prepared from carbon fiber sizing treated with 8102 PPAK have excellent mechanical properties,and the mechanics of composites prepared from carbon fiber treated with graphene oxide enhanced sizing agent(GO-8102PPAK)Performance is further improved.