Kinetics of 4,4′-diaminodiphenylmethane curing of bisphenol-S epoxy resin

The kinetics of the cure reaction for a system of bisphenol-S epoxy resin (BPSER), with 4,4'-diaminodiphenylmethane (DDM) as a curing agent, were studied by means of differential scanning calorimetry (DSC). Analysis of DSC data indicated that an autocatalytic behavior showed in the first stages of the cure, with the model proposed by Kamal, which includes two rate constants, k(1) and k(2), and two reaction orders, m and n. Rate constants k(1) and k(2) were observed to be greater when curing temperature increased. The over-all reaction order, m + n, is in the range of 2.5 similar to 3. The activation energies for k(1) and k(2) were 55 kJ/mol and 57 kJ/mol, respectively. Diffusion control is incorporated to describe the cure in the latter stages. (C) 1999 John Wiley & Sons, Inc.