A novel liquid imidazole-copper (II) complex as a thermal latent curing agent for epoxy resins

In this study, 1-cyanoethyl-2-ethyl-4-methylimidazole (1C2E4MI) was modified by copper chloride to improve its thermal latency towards epoxy resins. Unexpected complexation between 1C2E4MI and copper chloride was discovered, and two complexes which included a liquid and a solid were generated. The microanalytical results show that the ligand-metal ratios of these two complexes are 7:1 (liquid) and 1:1 (solid), rather than the theoretical 4:1 ratio. The liquid 1C2E4MI-copper (II) complex (Complex-L) exhibits superior miscibility with epoxy resins, and the resulting epoxy systems show distinctly prolonged pot life at 25 and 60 °C. Curing kinetic study indicates the epoxy system containing Complex-L can be cured using a similar manner like that containing 1C2E4MI. Moreover, the epoxy resin cured with Complex-L has glass transition temperature and tensile properties comparable to that cured with 1C2E4MI.Graphical abstract

Source: Polymer - June 16, 2019 Category: Chemistry Source Type: research