Examination of the surface properties of kaolinites by inverse gas chromatography: Dispersive properties

The application of inverse gas chromatography (IGC) for the examination of the surface properties of untreated kaolinite and kaolinites surface-treated with titanate coupling agents is discussed. This paper presents and discusses the dispersive properties expressed by γ_S^D, the dispersive component of the surface free energy, as determined at various temperatures. The γ_S^D values of all the samples were negatively correlated with the temperature of IGC measurement. At the same temperature of IGC measurement, the values of γ_S^D determined by IGC were significantly lower for the surface-treated kaolinites than for the untreated ones. The γ_S^D value of the kaolinite surface-treated with isopropyl triisostearoyl titanate (ITT) at 150°C exhibited a surface energy close to that (28.3 mJm^-2) of polyethylene with no surface polarity.