Characterization of thermally oxidized carbon fibre surfaces by ESCA, wetting techniques and scanning probe microscopy, and the interaction with polyethylmethacrylate. Development of a biocompatible composite material

The development of biocompatible weft knitted carbon fibre-reinforced thermoplastics needs optimization of each composite component: fibre, matrix and interface. The material investigated was a composite of polyethylmethacrylate reinforced with a knitted and sized T300 carbon fibre. After chemical removal of the fibre sizing, the fibres were thermally oxidized at temperatures between 400 and 600°C. Angle-resolved photoelectron spectroscopy (ESCA) and Wilhelmy surface energy measurements have been used to describe the modification of the surface chemistry by thermal oxidation. The surface morphology, visualized by scanning probe microscopy and scanning electron microscopy, indicates an increased surface roughness. The interaction between fibre and matrix was investigated by observing the microscopic wetting behaviour of the thermoplastic at sinter temperature by the solid-body wetting technique. It is found that the strength and failure mechanisms of the knitted fibre-reinforced composite are determined by the interface properties.