Mechanical, surface and interfacial characterisation of pitch and PAN-based carbon fibres

The mechanical and surface characteristics of pitch and PAN-based carbon fi bres were studied by tensile testing, XPS, SEM analysis and wetting measure ments. The pitch-based fibres had two different geometries, with circular a nd ellipsoidal (ribbon-shaped) cross sections. Plasma oxidation was used to treat the surface of the fibres. The interfacial characteristics of untrea ted and treated fibres were measured by fragmentation tests of single filam ent composites. The effect of the surface treatment on the mechanical, surf ace and interfacial properties of the fibres was determined and correlated. It was shown that a relationship exists between the ability of the surface to transfer loads and its oxygen content. Finally, the influence of the no n-axisymmetry on the interfacial parameters obtained in the fragmentation t ests was assessed. (C) 2000 Elsevier Science Ltd. All rights reserved.