Abstract: In this work, ionic liquids of 3-(2-amino-2-oxoethyl)-1-butyl imidazolium dicyanamide (AOBD) was used as curing agent for bisphenol A epoxy resin (E-51). The curing processes and the thermoset properties of AOBD/E-51 were fully characterized. Results show that AOBD is a high temperature curing agent for E-51, the optimum curing ratio and temperature range of AOBD/E-51 are 10:100 and 122-156℃, respectively, and the post-curing temperature is 178℃. The mechanical properties of the thermosets were characterized as follows. The tensile strength is 30.7 MPa, the tensile modulus is 3 233.1 MPa, and the elongation at break is 1.1%. The dynamic mechanical thermal analysis results show that the maximum loss factor, the glass transition temperature, the storage modulus, and the crosslinking density are 0.56, 174.8℃, 134.8 MPa, and 3 198.8 mol·m^-3, respectively. Based on the IR spectra in different curing processes, the -CONH₂ groups of AOBD react with epoxy groups at lower temperature, and then the anions react with epoxy groups further at higher temperature to achieve the whole curing processes. This study provides informative guidelines for choosing new curing agents of epoxy resin.

Key words: AOBD, epoxy resin, curing agent, tensile properties, curing kinetics