The Surface Treatment Study Of Different Carbon Fiber Physical Morphology

The surface properties of carbon fiber directly affect the interfacial properties of Carbon Fiber Resin Composite(CFRP),which ultimately has a great influence on composite properties.For carbon fibers with different surface physical morphology,the comparison and analysis of the surface treatment is very important to the preparation of carbon fiber and process of composite materials.In this study,two kinds of carbon fibers(T700S and T300)with similar modulus but different surface physical morphology were taken as research objects.After surface treatment under the same process,the carbon structure,elementcontent and functional groups of the surface,surface energy,fiber strength and interlaminar shear strength were analyzed,and the influence of carbon fiber surface physical morphology on the surface treatment was discussed:Compared with dry-wet spinning carbon fiber with clean surface,the wet-spinning carbonfiber with groove morphology was more easily destroyed,and the change of carbon fiber surface physical morphology was more significantly affected by surface treatment.Besides,it was easier to introduce oxygen-containing functional groups into the surface of the wet-spinning carbon fiber.After surface treatment,the surface O element content of the wet-spinning carbon fiber was increased by 47%and O/C by 65%.While the surface O element content and O/C of dry-wet spinning carbon fiber was increased by 25%and O/C by 31%,respectively.In our study,the change trend of tensile strengthof the two kinds of carbon fibersshowed the same,whichwere increased firstly and then decreased.But the strength of dry-wet spinning carbon fibers(T700S)varied less.The increase of the polar surface energy of the dry-wet spinning carbon fiber was more difficult and required a higher current density.Considering the research results of fiber strength and interlaminar shear strength of CFRP,the optimal surface treatment condition of HF30S dry-wet spinning fiber is as follows:current density 1.0 mA/cm2,treatment time 100s,electrolyte concentration 1.5mol/L.The optimal surface treatment technology of HF10 wet-spinningcarbon fiber is:current density 0.5 mA/cm2,treatment time 60s,electrolyte concentration 1.5mol/L.