A series of clay pillaring agents with amino, olefin, and epoxy groups were synthesized. These pillaring agents were used to modify montmorillonite clay by ion-exchange reactions. TGA studies showed that organoclays with imidazolium pillaring agents have a higher thermal stability than those with ammonium groups. The d-spacings of organoclays were not affected by the pillaring agent functional groups and were sensitive to the size of pillaring agents. The dynamic-mechanical properties of the resulting clay/epoxy composites determined by DMA were similar. The addition of these clays to this epoxy resin enhanced the T(g) value of the resulting composites and greatly enhanced the storage moduli versus the pure epoxy resin by 1.6-1.8 times at 135 degrees C. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 2430-2441, 2011