THE RELATION BETWEEN CARBON-FIBER SURFACE-TREATMENT AND THE FIBER SURFACE MICROSTRUCTURE

The effect of an electrochemical surface treatment on the surface micr ostructure of Tenax(R) high-tensile-strength carbon fibres is investig ated using a multi-technique approach. The fibres are treated in a lab oratory set-up, which simulates the production conditions. The surface functional groups are characterized and quantified, and their depende nce on the treatment intensity is determined. The surface chemistry is correlated with the fibre surface topography. It is observed that for increasing treatment intensity, the surface area does not increase si gnificantly (except at very high intensities, in which a porous struct ure is formed). This contrasts with the dispersive part of the surface energy, which increases with the treatment intensity. Moreover, both basic and acidic surface functionalities are formed, the relative prop ortions of which change with the treatment intensity. These phenomena can be interpreted in terms of the concentration of active sites, whic h increases with the surface treatment and may be related to 'basal pl ane edges' of the (disordered) graphitic fibre microstructure.