Dynamically Electrostatic Regulated Intermolecular Cross-Linking for Preparing High-Tough Recyclable Disposable Bioplastic with Rapid Sterilization

Natural polysaccharide bioplastics are a promising alternative for nondegradable food packaging; however, some properties cannot be fully matched by petrochemical plastics. Herein, a biodegradable, eco-friendly bioplastic is constructed through dynamic electrostatic induct intermolecular cross-linking. By entropy initiation and electrostatic self-assembly, the protonated chitosan (CC) can be tightly bound to the polyelectrolyte complex (QS) composed of the quaternary ammonium chitosan and sodium alginate, further inducing crystallization through hydrogen bonds, resulting in the tensile strength and toughness of natural polysaccharide bioplastic (QSCC1/7(20)) being 5.4 and 13.4 times that of QS, respectively. Concurrently, the water resistance and gas barrier properties are also remarkably elevated. Due to the synergistic antibacterial activity of –NH3 + and –N+(CH3)3 groups, the QSCC1/7(20) achieves 3 h rapid sterilization (≥95%) and at least 5 day long-term bacteriostasis (≥99%), leading to foldable QSCC1/7(20) that can effectively keep perishable fruit fresh for 8 and 7 days in static and dynamic situations, respectively. Furthermore, QSCC1/7(20) can be recycled by low-carbon and water-assistance sustainable processes. Therefore, this work offers a prospective way to substitute petrochemical plastic packaging.