Figure 2.

Curing reaction mechanisms of DGEBA and GA under the catalysis of DMP-30: (a) Detailed chemical structures of DGEBA, GA, and DMP-30; (b) The tertiary amine is able to open the anhydride ring to form carboxylate anion, which then opens the epoxy ring to yield ester and new alkoxide anion. The new anion then reacts with another anhydride; (c) The hydroxyl opens the anhydride ring to form a carboxylic group, which further reacts with the epoxy group and generate a new hydroxyl; (d) The tertiary amine, nonphenolic hydroxyl, and anhydride form a complex, which enhances the reactivity between the epoxy group and the anhydride.