A sodium smectite (NaS) with a cation exchange capacity (CEC) of 1.08 mol kg−1 was intercalated with methyltributylammonium cation (MTBA+) with proportions equivalent to 0.2, 0.4, 0.6, 0.8 and 1.0 times the CEC. The contents of adsorbed water and intercalated
MTBA+ in the prepared organosmectites (OSs) were determined by using the differential thermal analysis (DTA) and thermogravimetry
(TG) curves. The adsorbed water of 8% in the NaS decreases greatly in OSs with the increase of the MTBA+ content and reduces to 2.0% for the 1.0 CEC sample. This explains the gradual change of the NaS from hydrophilic to hydrophobic
character. Thermal degradation of the intercalated MTBA+ in OSs occurs approximately between 250–450°C. The oxidation of the formed charcoal to CO2 occurs between 450–850°C. The intercalated MTBA+ content for each OS is obtained from both the TG and carbon analysis. The results do not agree exactly, but both the results
tend to increase by increasing initial content of the MTBA+ in solution.