Preparation of high-strength, colored and multifunctional chitosan fibers via a novel strategy of enzyme-catalyzed phenolic-amine crosslinking within chitosan fibers in a swollen state.

This study prepared high-strength, colored and multifunctional polyphenol-chitosan fibers via a novel strategy of laccase-mediated phenolic-amine crosslinking within chitosan fibers in a swollen state. A dense covalent network within the fiber was formed through Michael addition and Schiff base reactions. Compared to unmodified chitosan fibers, the enzymatically cross-linked fibers exhibited significantly enhanced mechanical properties, with an increase of about 270% in dry tensile strength (up to 156.8 MPa) and excellent wet stability. In addition, the polyphenol-chitosan fibers were given color and different properties by the covalent cross-linking of polyphenols into the fiber. The polyphenol-chitosan fibers had stable colors and did not fade in the environment. They also had an exceptional antibacterial rate of 99.99% and excellent UV protection. This laccase-mediated phenolic-amine crosslinking strategy provides an effective, sustainable method for producing high-performance, bio-based functional fibers.