The purpose of this paper is to investigate a new group of chemical compounds as accelerators (1-imidazole derivatives – tertiary amines) for curing of isocyanate-epoxy resin matrix. During heating no reaction between epoxy group and active hydrogen in presence 1-substituted imidazole derivatives was reported.
The influence of accelerator type and content on curing process, thermal stability and chemical structure of hardened resin was determined using temperature modulated differential scanning calorimetry, dynamic mechanical analysis, heat deflection temperature, thermogravimetry (modulated and by activation energy – Ozawa method) and Fourier transform infrared spectroscopy. Additionally, the shear strength of epoxy compositions used as aluminium joints, at ambient and elevated temperature was determined.
With catalyst content increase the oxazolidone or isocyanurate rings content decreased, indicating enhanced density of cross-linking and thermal resistance. For all imidazole derivatives used (i.e. 1-methylimizadole, 1-ethylimidazole and 1-butylimidazole) accelerating of the curing process was observed (significant decrease of the curing start temperature was reported). The thermal resistance and shear strength was improved with accelerator content (increase of isocyanurate rings amount, and consequently oxazolidone ones).
Introducing of a new group of chemical compounds as new catalysts to isocyanate-epoxy resin material resulted in curing process acceleration, irrespectively of the imidazole derivative type.
Emerald Group Publishing Limited
Copyright © 2014, Emerald Group Publishing Limited