Thermal Latent System in Curing of Epoxides by Imidazoles Interacting of Charge Transfer with Imide Derivatives

Abstract

The addition effect of phthalimide derivatives (PIDs) on curing reactions of epoxy resins by imidazoles was investigated. The curing behavior and storage stability of the epoxy compositions containing imidazoles and PIDs were evaluated. As a result, the curing initiation temperature in the presence of PIDs were higher than that in the absence of PIDs. Moreover, the storage stability increased by the utilization of PIDs. The UV-Vis absorption spectrum of a mixture of PIDs and imidazoles suggested that the charge transfer interaction, which led to decreasing the nucleophilicity of imidazoles, resulted in the thermal latency. The present study provides the charge transfer interaction between PIDs and imidazoles in epoxy resins, which can be used for the construction of thermal latent systems for curing reactions of epoxy resins.