| The composition and structure of AR mesophase pitch were studied by means of elemental analysis, FT-IR and the differences of structure during the preparation were analysed. Carbon fiber obtained through melt-spinning, oxidization, carbonization from mesophase pitch, and the result of experiment showed that AR mesophase pitch has better properties at the temperature of 360℃, the pressure of 0.01MPa and the collecting rate of 500r/min. On the other hand , analyzing method of SEM proved that the cross section of carbon fiber was onionskin and onionskin-radiation.Some major elements influencing the modificatory effect of mesophase pitch-based carbon fiber during the process of electrochemical oxidation were comparatively analysed by the Orthogonal experiment. The optimized conditions of electrochemical oxidation were characterized through Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy etc. It is showed that the hydroxyl, carbonyl, carboxyl groups were analysed around the surface of carbon fiber, on condition that 24h HNO3(65%) pretreatment,180s electrochemical oxidation, 0.5A current intensity and 0.6mol·L-1 electrolyte concentration, which caused the increase of the points of chemical bond. On the other hand, the results proved that the ILSS of composite after Orthogonal design can be mounted to 45.324MPa which is higher by 24.1% and 49.4% than the process including electrochemical oxidation only and the raw carbon fiber respectively.In order to improve the interfacial binding force between carbon fiber and resin, the design of macromolecule coating was applied resulting in the ILSS improvement of composites. The result showed that ILSS can be mounted to 48.357MPa, which was better than non-surface treatment by the percentage of 59.4%. The mechanical and SEM data explained that better interfacial binding force was obtained by the way of better force transfer between carbon fiber and resin.
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