| Carbon fiber has the excellent properties such as high-strength and high-modulus, usually used as reinforcement with matrix producing composite, and widely used in Aero-Space field. Aqueous agent had bigger impact on the interface performance of composite,and aqueous sizing agent sizing carbon fiber can not only avoid carbon fiber surface to be polluted; but also protect the activity of surface functional group; and improve the bounding of carbon fibers; and carbon fiber can also be infiltrated to reduce the surface tension of carbon fiber and matrix resin, to strengthen the interface bonding degree of carbon fiber and matrix resin, to improve shear intensity between layer, Relatively, the process of preparation of Solvent type sizing agent agent is simple, and the applied range of aqueous agent is wide,but aqueous sizing agent avoided the shortcoming of environmental pollution caused by volatilization of low boiling point organic solvent, and resin easily remained on deflector roll, and increasing amount of carbon fiber lousiness. Thermosetting resin had big difference with High performance plastic resin. At present, sizing agent is in the majority with thermosetting epoxy resin, not being suitable for PES matrix resin system, so finding suitable aqueous sizing agent that can improve the interface performance of CF/PES composite was extremely important.This research material was carbon fiber JT-3K, and carbon fiber was carried out surface electrochemistry process with lmol/L NH4HCO3. Optimum parameters of electrochemical treatments was determined by the result of Raman test of carbon fiber and interlaminar shear strength of CF/EP resin composite material. When the Optimum electrochemical treatments time is 120s, and electric current of electrochemical process is 700mA, process of surface electrochemical treatment can reach requirement, interlaminar shear strength between carbon fibers reinforced epoxy resin composite material can reach 82.3MPa,which improve 18.2% than untreated,4.3MPa more than average value of interlaminar shear strength of Commercial T300/EP composite material. The result of Raman test showed that content of functional group of carbon fiber reached maximum under 700mA.Then, carbon fibers was carried out under the optimal condition of electrochemistry processes, and carbon fibers coated by PES solution and self-made PES emulsion,the main resin of which is same with matrix resin polyethers sulfone. PES emulsion is more effective than PES solution sizing carbon fiber. When concentration of sizing agent PES emulsion is 1%, interlaminar shear intensity of CF/PES composite can reach maximum 76.3MPa,14.4%more than the composite when PES solution sized carbon fibers, which improve 35.1%than unsized. Comparing the equilibrium moisture content of 1%PES emulsion sizing carbon fibers with the equilibrium moisture of 1%PES solution sizing carbon fibers, the equilibrium moisture content of PES emulsion sizing carbon fibers is 2.4 times of solution sizing carbon fiber, and It is 3.5 times of unsized,The result of DMTA tests showed that the tg of 1%PES emulsion sizing CF/PES composite was about 25? more than 1%PES solution sizing CF/PES composite, so that PES emulsion sizing effect is better than that of PES solution.Main ingredients of water-based PI is PAA. When Carbon fiber was coated by water-based PI agent, Carboxyl reacted with functional groups of surface of carbon fiber produced chemical bonds, which can improve interlaminar shear strength of composite. The trend of interlaminar shear strength was parabolic under different concentration of water-based PI sizing carbon fibers. Interlaminar shear strength reached maxium 70.6MPa,18.5%more than unsized,and equilibrium moisture content is 2.6times of unsizing carbon fibers, and amount of hair silk reduced 55.4%, and the crocking resistance performance improves. DMTA test showed when the sizing concentration of water-based PI is 0.5%, the tg of composite improved highest, about 90? more than unsized, so that water-based polyimide sizing carbon fiber can not only improve the effect of composite interface, but also can improve the heat resistance performance of composite materials.Carbon fiber was sized by water-based closed isocyanates agent, when temperature is more than 105?, isocyanates group is released, reacting with the functional group on surface of carbon fiber, which improve interlaminar shear strength of the Carbon fibers reinforced PES matrix composite. When sizing agent concentration was 1%, interlaminar shear strength of the composite reach maximum 71.6MPa,19.9% more than unsized, so the effect of sizing agent was good, and equilibrium moisture content is 4.9 times of unsizing carbon fibers, and amount of hair silk reduced, and the crocking resistance performance improves. In dynamic mechanically thermodynamics test showed when the sizing concentration of water-based isocyanate is 1%, the tg of composite is the highest, about 50? more than unsized, so that isocyanate emulsion sizing can improve interface performance of composite. |
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