The curing behavior of diglycidyl ether of bisphenol A (DGEBA) was investigated by differential scanning calorimetry with mixtures of silicon-containing amide-amines and diaminodiphenyl sulfone (DDS). Silicon-containing amide-amines were prepared by the reaction of 2.5 mol of 4,4'-diaminodiphenyl ether (E), 4,4'-diaminodiphenyl methane (M), 3,3'-diaminodiphenyl sulfone (mS), 4,4'-diaminodiphenyl sulfone (pS), bis(3-aminophenyl) methyl phosphine oxide (B), or tris(3-aminophenyl) phosphine oxide (T) with I mol of bis(4-chlorobenzoyl) dimethyl silane. Mixtures of the amide-amines and DDS at ratios of 0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25, and 1:0 were used to investigate the curing behavior of DGEBA. A single exotherm was observed on curing with a mixture of amide-amine and DDS. This clearly shows that the mixture participated in the cocuring reaction. The peak exotherm temperature depended on the structure and the molar ratio of amide-amines. With all of the amide-amines and DDS, a significant decrease in the kick-off temperature of the curing exotherm was observed on the incorporation of a 0.25 molar fraction of amide-amines. Thus, with the mixture, the curing temperatures were reduced and were lowest for ether-containing amide-amines and highest for methylene-containing amide-amines. The char yield was almost similar in the samples cured with amide-amines (E, pS, or mS) or DDS. The char yield was higher than for either of the constituents when a mixture was used. A synergistic behavior was observed when a mixture of E, M, mS, or pS and DDS was used, whereas mixture of B or T and DDS showed antigonism in the char yield. (C) 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1739 -1747, 2003.