Natural montmorillonite was pillared by various polyhydroxy cations. T
he resulting pillared layer clays (PILCs) were characterized by X-ray
fluorescence, X-ray diffraction (XRD) and infrared (IR) spectroscopies
. The thermal behaviour of Al-PILC was investigated in detail by a com
bonation of XRD, derivatography IR spectroscopy and a comparison to na
tural montmorillonite is given. It was found that thermal stability of
Al-PILC is lower than that of natural montmorillonite. However, heat
treatment in the stability region results in significant sintering of
natural montmorillonite, while the interlayer spacing of Al-PILC is ha
rdly affected.