REACTION BEHAVIOR OF DICYANDIAMIDE GLYCID YL ETHER-SYSTEMS

The cyano substituted guanidine, dicyandiamide, is widely used as a la tent curing agent in heat cured epoxy resins for laminates and prepreg fabrication. Dicyandiamide is nearly insoluble in liquid glycidyl eth ers causing some technical important problems during the processing. A lthough the cure mechanism and the formed network structure of dicyand iamide cured epoxy resins have been investigated extensively no analyt ical evidence for a predominating reaction course has been presented. Therefore, the aim of this paper is to give a survey on the literature and our own results dealing with the reaction behaviour of amine acce lerated heterogeneous and homogeneous epoxy dicyandiamide systems in a temperature range up to 140-degrees-C. A reaction mechanism is propos ed suggesting the dependence of the main reactions and some contradict orily discussed structures on a temperature depending tautomerization of the dicyandiamide.