Synthesis, curing kinetics and thermal properties of two novel quinoxaline-based mono- and bismaleimides

Abstract Two novel quinoxaline-based maleimide monomers, 2,3-diphenyl-6- maleimido-quinoxaline (MQMI) and 2,3-di(2-maleimido)phenyl-quinoxaline (BQMI), were successfully synthesized and characterized. Their structure was confirmed by 1H nuclear magnetic resonance (1HNMR) and Fourier transforms infrared (FTIR). The curing behavior was investigated by the rheological method and Differential scanning calorimetry (DSC). Starink method was used for the curing kinetics analysis of MQMI and BQMI monomers. The curing temperature and the apparent activation energy of BQMI were lower than that of MQMI, which indicated that the maleimide group location could affect its curing behavior. The thermal stabilities of the cured quinoxaline-based maleimide resins were detected by Thermogravimetric analysis (TGA), which implied that their decomposition temperatures were comparable with Poly(4,4’-bismaleimido diphenylmethane) (PBMDPM). However, the char yields (Yc) of PMQMI and PBQMI reached 54.1% and 57.3%, respectively, which were much higher than recorded values of PBMDPM.