Self-healing and reprocessable cellulose-based bioplastics based on side-group engineering approach

Developing cellulose-based bioplastics that combine mechanical robustness, self-healing, and reprocessability remains challenging because the dense hydrogen-bonded structure of cellulose provides cohesion but restricts the chain mobility required for interfacial reconstruction. Here, we report a side-group engineering strategy that balances these competing requirements by integrating flexible long aliphatic chains, metal-responsive aromatic groups, and Zn²⁺-mediated reversible interactions within a single cellulose-derived network. To implement this strategy, indole-3-acetic acid and oleic acid were sequentially grafted onto cellulose, followed by the introduction of Zn²⁺ to construct reversible dynamic junctions. The long aliphatic chains disrupted ordered chain packing and promoted molecular rearrangement, whereas the indole-derived aromatic groups enabled reversible network reconstruction. At an aromatic-group-to-Zn²⁺ molar ratio of 10:1, the resulting bioplastic achieved a tensile strength of 18.31 MPa and a tensile-strength healing efficiency of 92.14% after DMAc-assisted interfacial wetting followed by thermal treatment at 80 °C for 2 h. After four reprocessing cycles, it retained a tensile strength of 18.27 MPa and a tensile-strength healing efficiency of 90.53%. These results demonstrate that synergistically regulating chain mobility and reversible cohesion is an effective molecular design strategy for constructing mechanically robust, self-healing, and reprocessable cellulose-based bioplastics.