The effects of three organoclays (Cloisite 10A, 93A, and 30B) with different modifiers on the curing reaction of a liquid-crystalline epoxy (LCE) resin based on 4,4'-diglycidyloxybiphenyl and the curing agent sulfanilamide were studied. The curing kinetics of the LCE and clay composites were analyzed with differential scanning calorimetry. The Flyann-Wall-Ozawa and Kissinger-Akahira-Sunose methods were used to calculate the activation energies at different conversions. All three alkylammonium ions lowered the reaction activation energy and catalyzed the epoxy ring-opening reaction with the diamine curing agent. 30B, with two hydroxy groups of quaternary ammonium, showed the highest catalysis because the hydroxy groups facilitated the curing process. 10A and 93A had similar catalytic abilities. (c) 2005 Wiley Periodicals, Inc.