Structure-initiator activity dependence of aminimides as thermally latent initiators in the polymerization of glycidyl phenyl ether

Novel aliphatic aminimides were synthesized from the corresponding carboxylic acid esters, 1,1-dimethylhydrazine, and epoxides in 54–95% yields. Bulk polymerization of glycidyl phenyl ether (GPE) with 3 mol % of the aminimides was evaluated by DSC as a model process for curing of epoxy resin. All the aminimides showed no exothermic DSC peak below 120 °C but showed sharp exothermic peaks above 137 °C, indicating good thermal latency. Good relationships were observed between the calculated bond length from the carbonyl carbon to the α-carbon of the aliphatic group (RC), DSC onset temperatures, and the thermal dissociation temperatures (Td 's) of the aminimides. The aminimide with a longer RC bond length showed lower Td and DSC onset temperature, that is, higher activity.