SURFACE CHARACTERIZATION OF POLY(ACRYLONITRILE) BASED INTERMEDIATE MODULUS CARBON-FIBERS

The interface between the fibre and the matrix is a very important fac tor influencing the mechanical behaviour of composite materials. For s uperior composite performance, one must not only select optimal fibres and matrices, but also optimize the interface between them. However, the control of the interface properties is not an easy task. This work is an interdisciplinary and integrated approach to the problem. The e ffect of different degrees of a wet oxidative surface treatment on the surface of poly(acrylonitrile) based intermediate modulus carbon fibr es (Courtaulds IM CG43-750) has been studied using classical thermodyn amic as well as spectroscopic techniques, aimed at obtaining a complet e physical and chemical characterization of the fibre surface. The res ults show that all aspects of the fibre surface are influenced by the surface treatments, which are specially designed to improve the adhesi on between fibre and matrix. The study outlines the most important sur face features im proving th is adhesion. The results concerning the ch aracterization of the fibre surface contribute, when combined with mic romechanical tests, to clarifying the adhesion mechanisms, revealing, at the same time, a mechanical interlocking and a chemical interaction .