Self-healing and reprocessable bismaleimide-diamine thermosets containing disulfide linkages

Abstract

Mixtures of bis(2-maleimidoethyl) disulfide (BMIEDS), 4-aminophenyl disulfide (APDS), and Jeffamine® ED-600 (JA, an aliphatic polyether diamine) at a maleimide/NH2 ratio of 2/1 were prepolymerized at 170 °C and then compression-molded at 180 °C to obtain the cured products (BMIEDS-APDS-JAs). Similarly, BMIEDS/JA, bis(4-meleimidophenyl) disulfide (BMIPDS)/APDS/JA and BMIPDS/JA cured products (BMIEDS-JA, BMIPDS-APDS-JAs, and BMIPDS-JA) were prepared. The Fourier-transform infrared spectroscopy (FT-IR) of the cured products revealed that the maleimide/amine Michael addition reaction proceeded almost completely. The glass-transition temperature (Tg) and mechanical strength of the cured products decreased with the increase in JA weight fraction, and those of the BMIEDS-based cured products were lower than those of the BMIPDS-cured products. The highest JA fraction BMIEDS-APDS-JA and BMIESD-JA were healed three times at 100 °C, whereas none of the BMIPDS-based cured products exhibited self-healing properties. However, all the BMIPDS-based cured products were reprocessed by compression molding at 180 °C.