Thermally Reversible Cross-Linking of Recyclable Polyamide Materials Based on Schiff Base and Diels–Alder Reactions

Recyclability of cross-link polymer materials is essential to alleviate environmental pollution caused by discarded or damaged polymers. Herein, a facile method for producing recyclable polyamide materials is developed. Linear polymer chains are constructed by Schiff base reaction between glutaraldehyde (GD) and furandiamine (FD). The linear polymer chains are crosslinked by bismaleimide (BM) to give rise to polyamide material, named GF-BMs. The resulting GF-BMs polyamide material possesses strong tensile strength (78 MPa) and good solvent resistance from room temperature to 135 °C. Especially, the thermally reversible Diels–Alder covalent bonds and dynamic imine bonds in the polymer network have a synergistic effect on fast-reprocessing, self-healing, and recyclability, which provides a new idea for recyclable materials.