TG characterization of organically modified montmorillonite

Montmorillonite was modified with octadecyltrimethylammonium chloride, under different reaction conditions, as evidenced by TG and XRD. TG curves presented two degradation peaks (295 and 395°C). At low salt concentrations, only the 395°C-degradation appeared, which increased with reaction time to the limit of 9 g of salt/100 g of clay. The second peak presented a limit at 17/100 m/m of salt/clay ratio. XRD analysis confirmed clay organic modification as the basal distance increased, showing greater reaction time effect than the salt mass effect, and with only one d-spacing. This suggested that an intercalation complex was formed but also that octadecyltrimethylammonium was adsorbed on the external surfaces of clay particles. This revised version was published online in August 2006 with corrections to the Cover Date.