EFFECT OF CARBON-FIBER SURFACE ON INTERFACIAL ADHESIVE STRENGTHS IN CFRP

Surface properties of polyacrylonitrile (PAN) based carbon fibres and their adhesive strengths with epoxy resin are investigated. The surfac es of PAN-based carbon fibres were characterized by krypton adsorption and oxygen chemisorption, amount of acidic surface functional groups, X-ray photoelectron spectroscopy and Raman spectroscopy. Interfacial shear, interlaminar shear and transverse tensile strengths were measur ed as the interfacial adhesive strengths. The epoxy resin used for the embedded single filament specimens was the same as that used in the m atrix of the composites. Empirical equations between surface propertie s and adhesive strengths were calculated. All adhesive strengths in th is study showed the best correlation with the active surface area rati o, defined as the surface area ratio of oxygen chemisorption to krypto n adsorption. From these relationships, the effect of each surface pro perty on adhesive strength is discussed.