Thermally reversible cross-linked polyamides with high toughness and self-repairing ability from maleimide- and furan-functionalized aromatic polyamides

Polyamides having various amounts of maleimide (PA-MI) and furan (PA-F) pendent groups, respectively, as well as their cross-linked polymers (PA-MI/PA-F) were prepared. PA-MI/PA-F cross-linked polymers showed thermally reversible cross-linking behavior via Diels-Alder (DA) and retro-DA reactions. Cross-linked PA-MI/PA-F films exhibited enhanced toughness and mechanical properties compared to PA-MI and PA-F precursors. Moreover, PA-MI/PA-F films also showed thermal self-repairing behavior, which was observed in the micrographs and instron tests.