DSC AND FTIR ANALYSIS OF THE CURING BEHAVIORS OF EPOXY DICY/SOLVENT OPEN SYSTEMS/

The effects of solvents on the curing behaviors of an epoxy (diglycidy l ether of bisphenol-a) and dicyandiamide/2-methyl imidazole system ha ve been studied with differential thermal calorimetry (DSC) and Fourie r transform infrared spectroscopy (FTIR). From DSC analyses of the spe cimens prepared with unsealed aluminum pans, the reaction exotherm, th e time to maximal curing rate, the glass-transition temperature, the r ate constant, and the reaction order of the epoxy system decrease in t he presence of solvents were obtained. The changes were in the order o f toluene>tetra-hydrofuran>acetone and which are consistent with the o rder of their boiling points. The heat absorbed during the solvent eva poration consumed the curing exotherm and resulted in a change in temp erature dependent curing mechanisms. The results from FTIR spectra con firmed that the composition of the cured resin was influenced by the c uring temperature and the type of the solvent used. (C) 1998 Elsevier Science B.V.