Water-mediated fabrication of reprocessable and self-healing cellulose-based polyimine plastics

Abstract

The increasing environmental burden of petrochemical-based plastics has driven the urgent development of sustainable alternatives. Cellulose is a promising platform for biobased vitrimers, yet strong intermolecular hydrogen bonding severely limits its processability. Consequently, the homogeneous fabrication of cellulose-based polyimines without disrupting the intrinsic cellulose framework remains a key challenge. Herein, a ketone-functionalized, water-soluble cellulose levulinate ester (CLE) was prepared in a novel CO₂-based solvent system, followed by the fabrication of cellulose-based polyimine plastics (CPPs) via catalyst-free Schiff base reactions of CLE with a series of diamines in aqueous solution. The dynamic imine linkages formed in CPPs partially replaced hydroxy groups along the cellulose backbone, generating vitrimer-like polyimine networks. As a result, thermally triggered reversible imine exchange in the CPPs enabled reprocessability and self-healing behavior. Moreover, the materials demonstrated outstanding tensile strength (84.5 MPa) and Young's modulus (3.7 GPa), excellent moisture and solvent resistance, and both chemical degradability and biodegradability. Green metrics calculations provided quantitative support for the environmental profile of the present system. This water-mediated, catalyst-free fabrication strategy provides a molecular design approach for reconfiguring intermolecular interactions in cellulose, thereby establishing CPPs as a reprocessable platform for high-performance dynamic cellulose plastics.