Abstract:

Here we investigated the curing reaction between bisphenol epoxy resin E-51 and 1-hexyl-3- methylimidazole iron tetrachloride salt([C₆mim]FeCl₄) by differential scanning calorimetry. It was confirmed that the multi-level amine structure makes [C₆mim]FeCl₄ possible to be used as high-temperature curing agent for E-51. The curing reaction can be divided into two stages:at the first stage, the exothermic peak is about 120 ℃; at the second stage, the exothermic peak changes with the volume of [C₆mim]FeCl₄. When [C₆mim]FeCl₄ reacts with the mixed-amine to form a new curing agent, they exhibit apparent synergistic effect. The DSC results show that the new curing agent can react with E-51 under room temperature. The duration of exothermic peak is about 5 min at 30 ℃, and moreover, the duration decreases with the increasing temperature. The activation energy of the reaction calculated by the method of non-isothermal kinetics is 979 J/mol, which is only about 17% of the mixed-amine system. Finally, as the reaction order of the curing reaction is 0.5, it is believed to be a kind of random reaction.

Key words: hexyl-methylimidazole iron tetrachloride salt, bisphenol epoxy resin, high temperature curing agent, dynamics