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

Mixtures of bis(2-maleimidoethyl) disulfide (BMIEDS), 4-aminophenyl disulfide (APDS), and Jeffamine (R) ED-600 (JA, an aliphatic polyether diamine) at a maleimide/NH2 ratio of 2/1 were prepolymerized at 170 degrees C and then compression-molded at 180 degrees 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-APDSJAs, 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 glasstransition temperature (T-g) 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 degrees 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 degrees C.

Automated summary

Cured products with different compositions were successfully prepared by pre-polymerization and compression molding, and the occurrence of the reaction was confirmed by Fourier-transform infrared spectroscopy. Increasing the content of aliphatic polyether diamine resulted in a decrease in the glass transition temperature and mechanical strength of the cured products, with the BMIEDS-based ones showing lower performance than BMIPDS-based ones. BMIEDS-APDS-JA and BMIESD-JA exhibited self-healing properties, while BMIPDS-based products did not.