The cure kinetics of triglycidyl p-amino phenol (TGAP) epoxy resin with a diamine (4,4-diamino diphenyl sulphone [DDS]), reinforced with montmorillonite (MMT), has been studied by differential scanning calorimetry. The isothermal cure reaction consists of two parts: a rapid intra-gallery reaction, attributed to homopolymerization of the TGAP catalyzed by the MMT and the extra-gallery cross-linking reaction of the TGAP with the DDS. Increasing cure temperature promotes the intra-gallery reaction, which should promote an exfoliated nanostructure; this is confirmed by transmission electron microscopy. These results indicate that this system (TGAP/DDS/MMT) is an excellent candidate for achieving exfoliated polymer-layered silicate nanocomposites and identifies a protocol for optimizing the degree of exfoliation. POLYM. ENG. SCI., 54:51-58, 2014. (c) 2013 Society of Plastics Engineers