Raman microscopy of formamide-intercalated kaolinites treated by controlled-rate thermal analysis technology

Raman spectroscopy of formamide-intercalated kaolinites treated using contr olled-rate thermal analysis technology (CRTA), allowing the separation of a dsorbed formamide from intercalated formamide in formamide-intercalated kao linites, is reported. The Raman spectra of the CRTA-treated formamide-inter calated kaolinites are significantly different from those of the intercalat ed kaolinites, which display a combination of both intercalated and adsorbe d formamide. An intense band is observed at 3629 cm(-1), attributed to the inner surface hydroxyls hydrogen bonded to the formamide. Broad bands are o bserved at 3600 and 3639 cm(-1), assigned to the inner surface hydroxyls, w hich are hydrogen bonded to the adsorbed water molecules. The hydroxyl-stre tching band of the inner hydroxyl is observed at 3621 cm(-1) in the Raman s pectra of the CRTA-treated formamide-intercalated kaolinites. The results o f thermal analysis show that the amount of intercalated formamide between t he kaolinite layers is independent of the presence of water. Significant di fferences are observed in the C=O stretching region between the adsorbed an d intercalated formamide. Copyright (C) 2001 John Wiley & Sons, Ltd.