DISORDER INDUCED BY DE- INTERCALAT ION OF DMSO FROM KAOL IN ITE

ABSTRACT: De-intercalation f DMSO from well-crystallised kaolinites induced isorder. SEM, XRD and low-temperature IR were used to probe changes in morphology, layer stacking, and the environment of OH groups, respectively. The degree and type of disorder depended on the starting material nd on the method of removing the intercalate. Rapid removal by heating at 250~ caused smaller changes than more prolonged heating at lower temperature, or washing with water. Intercalation of polar organic compounds in kaolinite interlayers has been extensively investigated. In recent years the complex with dimethylsulphoxide (DMSO) has been the subject of several studies. DMSO is a small, highly polar molecule which forms an ordered structure with kaolinite. In papers dealing with kaolinite intercalates, the procedure adopted for introducing the organic material is generally carefully specified. It has been recognized that the method of preparation may affect the nature of the product, e.g. Lipsicas et al. (1986) attributed differences between the infrared (IR) spectra of their N-methylformamide and formamide intercalates and those described by Cruz et al. (1969) to the milder conditions of their experiments. Several investigators have addressed the question whether intercalation an