Epoxy adhesive formulations using latent imidazole metal cation complexes
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Complexes of 2-methylimidazole with cations from several metal sulfates were prepared and investigated as curing agents for epoxy resins. The reactivity of one-part formulations of these complexes with a bisphenol A type epoxy resin was determined by the differential scanning calorimetry and the pot life observed by viscosity measurements. Tensile lap shear tests at room temperature and at 120°C were used to evaluate the adhesive strength of the formulations directly after preparation as well as after one and three months of storage at room temperature.The DSC measurements showed much lower reactivity (7 - 32%) and higher reaction temperatures of the complex formulations in comparison to the mixtures with pure 2-methylimidazole. The viscosity of most formulations remained almost unchanged over the observed period of three months. The adhesive strength of the freshly prepared complex formulations is comparable to a formulation with pure 2-methylimidazole and decreases over time, depending on the type of metal cation and the cation-to-imidazole molar ratio. The obtained results indicate that complexes of 2-methylimidazole with cations are suitable as latent curing agents for epoxy resins.
1 - 1 - 2011
17 - 3 - 2011
- Pilawka, R., Spychaj, T. & Leistner, A. (2008). Compositions and epoxy materials hardened with imidazole and metal cation complexes. Polimery 53, 526-530 (in Polish).
- Hamerton, I., Howlin, J. B. & Jepson, P. (2002). Metals and coordination compounds as modifiers for epoxy resins. Coordination Chemistry Reviews 224, 67-85.
- Barton, J. M., Hamerton, I., Howlin, J. B., Jones, J. R. & Sh, Liu (1998). Studies of cure schedule and final property relationships of a commercial epoxy resin using modified imidazole curing agents. Polymer 39, 1929-1937. DOI: PIh S0032-3861(97)00372-8.
- Dowbenko, R. & Anderson, C. C. (1972). U. S. Patent No. 3 635 894. Washington, D. C.: U. S. Patent Office.
- Dowbenko, R. & Anderson, C. C. (1972). U. S. Patent No. 3 677 978. Washington, D. C.: U. S. Patent Office.
- Barton, J. M (1984), U. S. Patent No. 4 487 914. Washington, D. C.: U. S. Patent Office.
- Ohnishi, K. & Nishiguchi, Sh. (1998), U. S. Patent No. 5 789 498. Washington, D. C.: U. S. Patent Office.
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