A study of the mechanism of curing of the dicyandiamide-epoxydiane oligomer system in the presence of asymmetrical urea

• Published in: Polymer science. Series D, Glues and sealing materials Glues and sealing materials, 2015-04, Vol.8 (2), p.153-162
• Main Authors: Chursova, L. V., Tkachuk, A. I., Panina, N. N., Gurevich, Ya. M., Babin, A. N., Malkov, G. V.
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Polymer Sciences
• ISSN: 1995-4212; 1995-4220
• DOI: 10.1134/S1995421215020057

Catalyzed epoxy systems have been studied consisting of an ED-20 epoxy diane oligomer ED-20, a curing catalyst (dicyandiamide (DCDA)), and an accelerator (an asymmetric urea based on toluene diisocyanate). The chemical composition and structure of the catalyzed epoxy systems have been established by IR and NMR spectroscopy in the initial and cured states. The influence of the composition of the complex catalyst system of curing on the mechanisms of chemical transformation of epoxy system has been considered. It is shown that the products of interaction of epoxydiane oligomers with DCDA in the presence of the accelerator-asymmetric urea of Dyhard UR500 brand-is a complex system consisting of chains of polyesters produced by a chain growth mechanism and amine sites, as well as interaction products of epoxy groups with imines, isocyanates, and hydroxyl groups with nitriles.