Chemical interactions between the carbon fibre surface and epoxy resins

Surface oxides on various carbon fibres were determined after modified oxidation treatment with nitric acid. Improved wetting was investigated by contact angle measurements. The results of these systematic studies are correlated with the mechanical properties of UD-composites, prepared from the matrix precursors with which the wetting experiments have been performed. A possible mechanism of the bonding between epoxy matrix precursors and reinforcing fibres was determined by contact angle measurements, by surface tension measurements and by chemical analysis of the chemisorpted diamine hardener.