Complexity of intercalation of hydrazine into kaolinite - A controlled rate thermal analysis and DRIFT spectroscopic study

Controlled rate thermal analysis (CRTA) allows the separation of adsorbed and intercalated hydrazine. CRTA displays the presence of three different types of hydrogen-bonded hydrazine in the intercalation complex: (a) The first is adsorbed loosely bonded on the kaolinite structure fully expanded by hydrazine-hydrate and liberated between approx 50 and 70degreesC (b) The second intercalated hydrazine is lost between approx 70 and 85degreesC. (c) The third type of intercalated-hydrazine molecule is lost in the 85-130degreesC range. CRTA at 70degreesC enables the removal of hydrazine-water and results in the partial collapse of the hydrazine-intercalated kaolinite structure to form a hydrazine-intercalated kaolinite. Removal of the adsorbed hydrazine enables the DRIFT spectra of the hydrazine-intercalated complex without any adsorbed hydrazine to be obtained. A band at 3626 cm(-1) attributed to the inner surface hydroxyls of kaolinite hydrogen bonded to hydrazine is observed. The intercalation of hydrazine-hydrate into kaolinite is complex and results from the different types of surface interactions of the hydrazine with the kaolinite surfaces. (C) 2002 Elsevier Science (USA).