Dynamic Imine Bond-Enabled Starch-Based Materials with Self-Healing and Recycling Properties

Starch-based plastics represent a promising approach to addressing the environmental pollution caused by petroleum-based plastics. However, achieving a balance between high mechanical strength, ductility, and multiple processing capabilities in starch-based plastics remains a significant challenge. In this study, a novel plastic was successfully developed via the dynamic cross-linking of dialdehyde starch (DAS) and amines with different functionalized side chains. The results demonstrated that the DAS bioplastics exhibit good mechanical strength (26.7–44.0 MPa) and a high Young’s modulus (220–1200 MPa), surpassing those of most previously reported starch-based plastics. The long chain of the 12-carbon atoms in the diamine segment endows the film with foldability, allowing it to be freely folded into various shapes such as cylinders or cones. Additionally, the DAS bioplastics displayed thermal stability and good solvent resistance (>7 days). Furthermore, the DAS bioplastics exhibited good antibacterial properties, achieving antibacterial efficiencies exceeding 98% against Staphylococcus aureus and Escherichia coli, thereby eliminating the need for additional antibacterial agents in the plastic formulation. The DAS bioplastic underwent degradation in soil over a period of 56 days, resulting in a weight loss of more than 60.5%. Additionally, relatively pure DAS could be successfully recovered from the bioplastic within 30 min when treated with an acidic solution. Therefore, this study presents a novel method for the preparation of high-performance starch-based packing plastics.