Thermal behavior and decomposition of kaolinite-potassium acetate intercalation composite

A series of kaolinite-potassium acetate intercalation composite was prepared. The thermal behavior and decomposition of these composites were investigated by simultaneous differential scanning calorimetry-thermogravimetric analysis (DSC-TGA), X-ray diffraction (XRD) and Fourier transformation infrared (FT-IR). The XRD pattern at room temperature indicated that intercalation of potassium acetate into kaolinite causes an increase of the basal spacing from 0.718 to 1.428 nm. The peak intensity of the expanded phase of the composite decreased with heating above 300 degrees C, and the basal spacing reduced to 1.19 nm at 350 degrees C and 0.718 nm at 400 degrees C. These were supported by DSC-TGA and FT-IR results, where the endothermic reactions are observed between 300 and 600 degrees C. These reactions can be divided into two stages: (1) removal of the intercalated molecules between 300 and 400 degrees C. (2) dehydroxylation of kaolinite between 400 and 600 degrees C. Significant changes were observed in the infrared bands assigned to outer surface hydroxyl, inner surface hydroxyl, inner hydroxyl and hydrogen bands. (C) 2010 Elsevier B.V. All rights reserved.