Direct Eutectic Plasticization Strategy for Solvent-Free, Recyclable, and Hydrophobic Ethyl Cellulose-Based Bioplastics

The valorization of cellulose into melt-processable bioplastics is persistently impeded by its intractable hydrogen-bonding network, typically necessitating energy-intensive regeneration or irreversible chemical cross-linking. Here, a “direct eutectic plasticization” (DEP) strategy is reported for fabricating high-performance ethyl cellulose-based bioplastics (ETP) via rapid, solvent-free solid-state hot-pressing. By orchestrating the supramolecular assembly of ethyl cellulose, thymol, and palmitic acid (PA), a thermodynamically reversible “locking–unlocking” network is constructed within seconds to minutes. The incorporation of PA facilitates molecular lubrication and surface segregation, yielding an exceptional combination of high transparency (>90%), robust strength (∼25 MPa), and superior hydrophobicity (>110°). Crucially, this all-physical network enables exceptional mass retention (∼99%) during recycling, retaining structural integrity over 20 reprocessing cycles. Furthermore, the ETP material demonstrates versatile functionalities, serving as a high-strength structural adhesive and active packaging, effectively mitigating mass loss and enzymatic browning in fresh-cut produce. This work provides a paradigm for transforming biomass into high-performance bioplastics.