Dynamically Crosslinking Cellulose Nanofibers and\nEpoxy Soybean Oil toward Tough, Recyclable, and Degradable Bioplastics

Developing\ncellulose nanofiber-reinforced bio-based recyclable\nand biodegradable plastics can be a fundamental solution to the global\naccumulation of plastic waste. Herein, we present a bio-based supramolecular\nplastic with a “reinforced-concrete” architecture achieved\nthrough the establishment of cellulose nanofiber crosslinking network\nand dynamic boron oxide crosslinking between cellulose nanofibers\n(CNF) and epoxy soybean oil. Termed as DACNF-ESO, this bio-based supramolecular\nplastic exhibits an impressive tensile strength of ≈41 MPa\nwhile maintaining flexibility. After being subjected to a high temperature\n(150 °C) or water immersion for 7 days, the tensile strength\nof DACNF-ESO plastic remains superior to that of polyethylene (PE)\nplastics. The dynamic reversibility of boron oxide in DACNF-ESO plastic\nenables temperature adaptability and welding capability and allowed\nfor multiple recycling cycles. Complete degradation of DACNF-ESO in\nsoil without the generation of any harmful substances can be achieved\nwithin a period of 80 days. The present study offers a novel design\nprinciple for high-performance recyclable polymers as sustainable\nalternatives to conventional plastics. Moreover, both in vivo and\nin vitro tests demonstrate the exceptional biocompatibility of DACNF-ESO\nplastics, thereby expanding their potential applications in food,\nbiological medicine, cosmetics, and flexible electronic substrates.