Effect of Low Power Plasmas on Carbon Fibre Surfaces. Part 2. A Comparison between Low and High Modulus PAN Based Fibres with Pitch Based Carbon Fibres.

摘要

A comparison of the effects of a variety of low power (<1W) plasmas (air, NH3 and N2) on highly ordered pyrolytic graphite (HOPG), polyacrylonitrile (PAN)-based and pitch based carbon fiber1 has been studied using X-ray photoelectron spectroscopy. Grazing angle techniques have been used to probe only the first 12-15 A of the fiber surface. Plasma treatments were carried out in an in situ plasma cell which was attached to a PHI 5400 X-ray photoelectron spectrometer. This enabled the immediate effects of the plasma to be studied before the treated surface was exposed to air. The reactivity towards a particular plasma is shown to be largely dependent on the structure of the fiber surface. Air plasma proved much more reactive to the fiber surface than either nitrogen or ammonia plasma resulting in alcohol type groups being incorporated onto the basal planes and carboxyl groups onto the edge sites. Ammonia and nitrogen plasmas only attacked the edge sites with the formation of aliphatic and aromatic amines (C-NH2) together with small number of immines (C=NH).