Investigation of the influence of acidic and basic surface groups on carbon fibres on the interfacial shear strength in an epoxy matrix by means of single-fibre pull-out test

The influence of surface state (acidic and basic surface oxides) on carbon fibres on the interfacial shear strength (IFSS) in an epoxy matrix was studied by means of the single-fibre pull-out method, which is performed in a high-stiffness test apparatus. The fibre surface tension and the thermodynamic work of adhesion were calculated. The surface compositions of the carbon fibres were studied by ESCA. IFSS was compared with thermodynamic works of adhesion and the measured amount of oxygen containing surface groups.