Characterization of pristine and purified organobentonites

Pristine and purified Argel sodium bentonites were organically modified with quaternary ammonium and phosphonium surfactants by ion exchange reaction in order to investigate the effect of the chemical identity of the surfactant and of the clay purification procedure in the intercalation process, final structure and thermal stability of organobentonites. The bentonites were characterized by X-ray diffraction analysis, thermogravimetric analysis and Fourier transform infrared spectroscopy. The bentonite purification treatment and, especially, the chemical structure of surfactant affected the thermal behavior of the organobentonites. The phosphonium modified bentonites were thermally more stable than those modified with ammonium, particularly the purified bentonite. These results seem to be promising regarding to the potential application of phosphonium modified Argel bentonites for the melt processing preparation of nanocomposites with polymeric matrices requiring high processing temperatures.