Abstract
Optimization of interface by changing the chemical properties of fiber surface is essential for the improvement of composite properties. Four kinds of carbon fibers with different surface treatments were produced specially at an industrial manufacturing plant in order to study the relation between the interfacial properties and mechanical properties of carbon fiber reinforced composites. In this report, the influence of the surface oxygen content of carbon fiber on the interfacial adhesion strength was examined by using the single fiber fragmentation technique. The interfacial shear strength (τ) and the interfacial transmissibility (κ) of four carbon fibers were investigated on the single filament embedded test specimens. Both τ and κ increased with increasing surface oxygen content, but τ showed different tendency in the case of sized and non-sized fibers. The distribution of the fractured fiber length was wide when the surface oxygen content was low, but it became narrow with increasing oxygen content. These results suggest the possibility that the adhesion strength at the interface is not uniform, and the unevenness is increasing with decreasing surface oxygen content.
