Adsorption of polymers: Polystyrene on carbon

The adsorption of polystyrene from toluene solution on a carbon black has been studied at 25°C. under varying conditions of dryness. The isotherm for adsorption on the relatively dry carbon black exhibited a characteristic steep initial rise as a function of concentration and attained a saturation value. Larger molecules appear from intrinsic viscosity studies to be adsorbed preferentially. The rate of desorption appears to be so low that, for time periods of the order of two weeks, the adsorption of polystyrene is effectively irreversible. The total adsorption of polymer is decreased by extreme drying and by saturating the system with water.