THE EFFECT OF MICROWAVE PLASMA TREATMENT ON THE SURFACE-ENERGY OF GRAPHITE AS MEASURED BY INVERSE GAS-CHROMATOGRAPHY

The surface energy characteristics of natural graphite were modified by various microwave (2,4 GHz) plasma treatments (n-butyl alcohol, ammonia and n-butyl amine), and measured using inverse gas chromatography (I.G.C.), according to a new analytical method. The treatments were carried out indirectly (by placing the samples next to the microwave cavity) on natural graphite powders (150-250 mu-m) used either "as received" (GI) or after heat treatment at 800-degrees-C under argon (G II). While significant increases of both London dispersive component and expected acid-base character could thus be induced on G II, the changes are much less pronounced on G I, which is probably protected by some adsorbed contaminant film.