METHOD FOR TREATING SURFACE OF HIGH ELASTIC MODULUS CARBON FIBER

摘要

PURPOSE:To enable the surface treatment of high elastic modulus carbon fibers wherein the surfaces of inactive sites of the carbon fibers are also sufficiently treated and the adhesivity of the carbon fibers to matrix resins is sufficiently improved by subjecting the surfaces of the carbon fibers to an electrolytic oxidation treatment at a specific application voltage and under a specific pulse supplying condition. CONSTITUTION:An electrolytic oxidation treatment is applied to the surfaces of many high elastic modulus carbon fibers (e.g., 1000-24000 fibers) under set conditions where the application voltage is >=10V and wherein electric pulse-feeding intervals comprise electricity-feeding periods of <=0.02sec and feeding-stopping periods >=5 times longer than the electricity-feeding periods. The conditions permit the sufficient treatment of the difficultly oxidized inactive sites of the carbon fibers, the minimized generation of pitching also on the readily oxidized active sites of the carbon fibers and the effective and excellent treatment of the surfaces of the fibers without causing the lowering of the strength of the carbon fibers. The treated fibers exhibit sufficient adhesively to matrix resins as reinforcing fibers for composite materials and do not cause the lowering of the strength of the composite materials.