The effect of an octadecylammonium-exchanged montmorillonite on the curing kinetics of a thermoset system based on a bisphenol A epoxy resin and a poly(oxypropylene)diamine curing agent Were Studied with differential scanning calorimetry (DSC) in isothermal and dynamic (constant-heating-rate) conditions. Montinorillonite and the prepared composites were characterized by X-ray diffraction analysis and simultaneous DSC and thermo-gravimetric analysis. The analysis of the DSC data indicated that the intercalated octadecylammonium cations catalyzed the epoxy-amine polymerization. A kinetic model, arising from an autocatalyzed reaction mechanism, Was applied to the DSC data. Fairly good agreement between the experimental data and the modeling data was obtained. (c) 2006 Wiley Periodicals, Inc.