Preparation Of CF/PEEK Composites And Modification Of CF By SPEEK

Poly(ether ether ketone)(PEEK)is a high performance thermoplastic engineering plastic with excellent high temperature resistance,corrosion resistance and excellent mechanical properties.Carbon Fiber(CF)Reinforced PEEK composites have great potential in the field of aerospace.The prepreg used in traditional thermoplastic composites is a prepreg made by the method of melting impregnation.This process is difficult and cost high.And because of the high hardness of PEEK,this prepreg is difficult to process the forming of surface structure.In this paper,a two-dimensional braiding method is used to make flexible preforms of carbon fiber and PEEK fiber.The best process parameters of this preform in molding process are studied.The conclusion is that the molding pressure is 0.6MPa,from room temperature to 370? to 30 min,cooling to 310? for 1h,and finally cooling to room temperature.PEEK is a semi crystalline resin,which can produce different crystalline state under different molding temperature system s.This state of crystallization will have an important effect on the mechanical properties of CF/PEEK composites.In the isothermal crystallization stage of the molding temperature system,4 different temperature conditions were set up to study the influence of the temperature of the isothermal crystallization stage on the crystalline state of PEEK.The results showed that the higher the crystallization temperature of the isothermal crystallization was,the greater the crystallinity of the crystalline PEEK was,and the isothermal crystallization temperature could not change the crystal type of the PEEK.The CF/PEEK multidirectional laminates with 12 layers(0 /90 degrees)s are prepared by using the optimum technological conditions.The tensile and bending mechanical properties are tested.The tensile strength is 735.5MPa,the tensile modulus is 68.92 GPa,the bending strength is 691.02 MPa.The analysis of the damage is obtained by using ABAQUS software,and the mechanical properties of CF/PEEK composites are affected.The factor of further improvement is low interlaminar shear strength.Sulfonated PEEK(SPEEK)was prepared by the chemical reaction between PEEK and concentrated sulfuric acid.The chemical state and heat resistance of SPEEK were characterized.The results showed that the chemical state of SPEEK with different sulfonated degrees was unchanged.The thermal weight loss of the sulfonated SPEEK was less than 5% at 370?,which met the heat resistance of the sizing agent in the molding process of CF/PEEK composites.Sexual requirements.The surface modification of depulp T300 carbon fiber was prepared by using SPEEK and DMF solution.The results showed that the best sizing effect was obtained when the concentration of the solution was 0.07%g/L.SPEEK modified carbon fiber on the surface of depulp T300 carbon fiber by introducing polar group,which effectively improved the surface energy of T300 carbon fiber,and increased the amplitude to 47.07%,which was close to the surface energy of the original sizing agent.Because of the high thermal stability of SPEEK and good compatibility with PEEK,the interfacial strong shear degree between carbon fiber monofilament and PEEK resin is improved,and the increase is 38.03%.