In this study

bisimide-containing diamine monomer (BIDA) was synthesized by using 6FDA and ODA as starting materials. Thermoset polyimide (PI) thin film containing dynamic imine bonds was then fabricated by reacting BIDA with terephthalaldehyde and tris(2-aminoethyl)amine

via

amine-aldehyde condensation reaction. The resulting PI thin film exhibited outstanding thermal stability and high mechanical strength

whose glass transition temperature as well as thermal decomposition temperature were up to 224℃ and 385℃

and tensile strength was above 90MPa

tensile modulus 2.16GPa

the highest value of the reported dynamic covalent polymers. The stress relaxation behavior of the film at different temperatures was investigated by dynamic mechanical analyzer

and the activation energy of the dynamic PI was calculated to be 222. 7kJ/mol. In this study

the primary amine-promoted mechanism was utilized to realize the rehealability of the thermoset PI films under mild conditions. The designing concept is expected to expand to other dynamic covalent polymer systems

and it is also expected to open many new possibilities for future development of novel high-performance

malleable

and rehealable thermoset polymers.