Chitosan/polyethylene glycol diglycidyl ether/aminated lignin composite coating to enhance wet strength of paper as a low-carbon alternative to single-use plastics.

The potential of paper as a plastic alternative is hindered by limited water resistance and mechanical strength. To address these challenges, this study developed a water-soluble chitosan/polyethylene glycol diglycidyl ether (PEGDE)/aminated lignin (AL) composite coating (CPA), which significantly enhanced the mechanical strength and water resistance of paper through molecular crosslinking and interface enhancement strategies. The CPA formed a dense crosslinked network on the surface and within the pores between fibers, enhancing the wet tensile strength of the paper by up to 75×. Moreover, the CPA retained biodegradability, allowing the coated paper to degrade in soil within 140 days. Additionally, CPA coated paper products, such as straws and mulches, exhibited excellent performance and a low carbon footprint, highlighting their potential as eco-friendly alternatives to plastics. This simple, scalable approach advances the development of sustainable, biodegradable paper-based materials.