Characterization of the cure of some epoxides and their sulphur-containing analogues with hexahydrophthalic anhydride by DSC and TGA

Abstract

A series of curing reactions of epoxides and different substituted (1,3-oxo-thiolane-2-thione)s with hexahydrophthalic anhydride in the presence of 2,4,6-tri( dimethylaminomethyl) phenol have been characterized by nonisothermal and isothermal differential scanning calorimetry (DSC). The DSC method was employed to investigate the thermal behavior of the systems cured and to evaluate the short-term stability of one-pot compositions. It was found that the cure processes of novel sulphur analogues of epoxides were generally described through lower (absolute) values of enthalpy of curing; on the other hand, the cure onset and the peak maximum temperatures were considerably higher. To evaluate the thermal stability of the networks obtained, thermogravimetric analysis (TGA) was applied. Its use allowed us to observe that derivatives of (1,3-oxothiolane-2-thione)s were thermally more stable that their analogue epoxides (up to 25°C) and the degradation profiles depended on the steric hindrancesand interactions introduced by the substituents used. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 451–460, 1998