Biomass-Based Functional Composite Resins with Recyclable and Shape Memory Properties

A key challenge in developing advanced functional thermosets lies in designing molecular architectures capable of integrating different specific performances into one material to meet diverse application demands. Here, a chitosan-derived trifunctional compound containing maleimide groups was used to directly cross-link tung oil-based polymer for fabricating multifunctional composite bioresins with reversible Diels-Alder bonds. The reversible cross-linking networks within resins were featured with stress relaxation, thermal reprocessability, and recyclability. The retro D-A reaction at relatively high temperatures provided the dynamic characteristics of the resins while ensuring their dimensional stability. Moreover, chitosan enhanced the mechanical properties of the resins while forming supramolecular hydrogen bonds via its abundant amino/hydroxyl groups, realizing shape memory of the resins. Furthermore, the synergistic interaction between chitosan functional groups and hydrogen bonding also imparted proton conductivity to the resins. This work provided a molecular design paradigm that harmonizes multifunctional integration in fully biomass resins, aiming for high-value applications.