A strong, biodegradable, and closed-loop recyclable bamboo-based plastic substitute enabled by polyimine covalent adaptable networks

Environmental pollution caused by nondegradable fossil-based plastics is one of the biggest global concerns. Bamboo, which is a renewable and biodegradable biomass resource, is a promising material for developing green plastic substitutes. However, the processing (e.g., thermal processing) of bamboo into plastic substitutes remains a considerable challenge because bamboo is a stable multicomponent structure crosslinked via strong hydrogen bond (H-bond) and covalent-bond interactions, which results in its non-thermoplastic characteristic. Herein, bamboo powders (BPs) were integrated into polyimine (PI) covalent adaptable networks (CANs) using a simple heat-pressing approach, which helped us successfully fabricate a thermally processable composite film (BP/PI). The heat-driven dynamic network exchange characteristic of PI also provides BP/PI with excellent reshaping, rehealing, and remolding capabilities. The multiple H-bond interactions between BPs and PI provide BP/PI with excellent tensile strength (45.2 MPa) and flexural strength (121.9 MPa). BP/PI also exhibits remarkable water and organic solvent resistance, chemical degradability, closed-loop recyclability, and biodegradability. This attractive BP/PI material represents a high-performance and ecofriendly plastic substitute.