Grafted organic derivatives of kaolinite: I. Synthesis, chemical and rheological characterization

Several new interlayer-grafted derivatives of kaolinite were synthesized by esterification of inner-surface hydroxyl groups with alkanols, diols and glycol mono-ethers starting With the dimethyl sulphoxide intercalate. The derivatives were characterized by X-ray powder diffractometry, thermal analysis, Fourier transform infrared spectroscopy and transmission electron microscopy. The grafted molecules are arranged in monolayers between the kaolinite layers, with typical basal spacings of similar to 11.3 angstrom. Rheological studies of aqueous dispersions of the modified kaolinites revealed an exponential increase of the yield value and apparent viscosity with increasing alkyl chain length of the grafted molecules.