The effect of an organically modified montmorillonite (OMMT) on the curing kinetics of a thermoset system based on a bisphenol A epoxy resin and a poly(oxypropylene)diamine curing agent were studied by melons of differential scanning calorimetry (DSC) in isothermal and dynamic (constant heating rate) conditions. Montmorillonite and prepared composites were characterized by X-ray diffraction analysis (XRD) and simultaneous differential scanning calorimetry-thermogravimetric analysis (DSC-TGA). Analysis of DSC data indicated that the presence of the filler has a very small effect on the kinetics of cure. A kinetic model, arising from an autocatalyzed reaction mechanism, was applied to the DSC data. Fairly good agreement between experimental and modeling data was obtained. (c) 2005 Wiley Periodicals, Inc.