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In this paper , a new treatment method based on polyacrylonitrile (PAN) based carbon fiber treated by supercritical carbon dioxide (SCCO2) is proposed. This method aiming to obtain a controlled interface is green and pollutionless . The surface state of carbon fibers both untreated and treated on different temperature was studied by using SEM, AFM and XPS. The results show that SCCO2 can erode the surface of carbon fibers. Roughness of modified carbon fiber is higher than that of the untreated. Interfacial properties of the treated carbon fiber /epoxy microcomposites were improved. Interfacial shear strength (ILSS) of CFRP shows that treated carbon fiber /epoxy at a lower temperature can be increased by 17.35%, which means that an effect of optimized interface is obtained.

The weight loss rate, FTIR characteristic, static mechanical properties and dynamic mechanical properties of neat epoxy resin and glass fiber/ epoxy resin laminates (GF/EP) after thermal-cold cycling were studied in this paper. The rule of static tensile and flexural strength of neat epoxy resin and GF/EP after ageing was investigated through the static mechanical properties analysis. The ageing mechanism of GF/EP was studied by analyzing the storage modulus (E′), loss modulus (E"), loss factor of GF/EP and FITR of epoxy resin. The results show that the weight loss rate increases with the ageing time，which is up to 9% after 400 times ageing cycle. The strength and flexural strength of GF/EP decreased by 6% and 21% after ageing, while the tensile strength of neat epoxy resin increases by 8% and its flexural strength increases slightly after ageing. The mechanism analysis reveals that internal defects of GF/EP would be induced by thermal-cold cycling stress, which results in the interface bonding strength dropping and the performance reducing.