Mono N-Alkylated DABCO-Based Ionic Liquids and Their Application as Latent Curing Agents for Epoxy Resins

Research on ionic liquids is constantly providing information on their new and more advanced applications. Undoubtedly, the use of latent curing agents for epoxy resins is one of the most interesting applications of this group of compounds. In this work, a detailed description of the synthesis and physicochemical studies of DABCO-based (1,4-diazabicylo[2.2.2]octane) ionic liquids is presented. Their most valuable feature is that they can be latent curing agents for polymerization of epoxy resins, which in turn can be used, when combined with fibers, as composites with special, new properties. The research includes detailed discussion of synthesis of new DABCO-ILs, focusing on obtaining pure compounds and expanding current knowledge on the subject. Thermal (DSC) and chromatographic (IC) properties have been discussed for all presented salts. Furthermore, ionic liquids with dicyanamide and triflate anion have demonstrated the ability to initiate polymerization of epoxy resins. Subsequently, all mixtures were cured into cubical shape and were subjected to the Shore hardness test (SHT). The main advantages of the obtained ILs are (i) the ability to store ionic liquids/epoxy resin mixture for prolonged periods of time without deterioration of curing properties and (ii) a significantly lower quantity of ionic liquids used in the process of curing epoxy resins.