Controlled chemical oxidation of carbon fibres: An XPS–XAES–SEM study

High-modulus, polyacrylonitrile-derived carbon fibres were chemically oxidized in concentrated sulphuric acid containing potassium permanganate. The pre- and post-oxidation surface status of the fibres was characterized by x-ray photoelectron spectroscopy, x-ray-excited Auger spectroscopy and scanning electron microscopy. Tests were made to evaluate the effects of temperature, time of treatment and permanganate concentration. The overall results are discussed in terms of flexibility and easiness of the treatment and of reproducibility of the chemical composition of the oxidized fibre surface.