A self-healing and recyclable polyurethane-urea Diels–Alder adduct synthesized from carbon dioxide and furfuryl amine

The fabrication of self-healing and recyclable CO2-based polymeric materials meets the requirement of sustainable development. By introducing reversible hydrogen bonds and heat-responsive Diels–Alder bonds, a new, environmentally friendly, self-healing and recyclable polyurethane-urea Diels–Alder adduct (PUUa-DA) was successfully synthesized using CO2 and furfuryl amine as renewable feedstocks. PUUa-DA was semi-crystalline and exhibited high thermal stability, 5% weight loss temperature being above 220 °C. Moreover, PUUa-DA with a cross-linked structure showed a tensile stress of 18.5 MPa, a modulus of 151 MPa and an elongation at break of 136%. The dynamic Diels–Alder bonds and hydrogen bonds provide the self-healing response and contribute to 94% recovery of the tensile strength upon heating. Therefore, PUUa-DA will have potential applications as a functional material in a wide range of practical fields. The synthesis of PUUa-DA using CO2 and bio-based furfuryl amine will be of importance in green and sustainable chemistry.