Chitosan grafting via one-enzyme double catalysis: An effective approach for improving performance of wool.

Chitosan is considered as a green additive with broad application prospects due to its advantages like biodegradability and antibacterial ability. Herein, we proposed an effective chitosan grafting approach via "one-enzyme double catalysis" strategy which aimed at functionalizing wool fibers to achieve bidirectionally multiple covalent crosslinking between chitosan and wool by laccase/2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) mediated oxidization. The mechanism was studied using models of wool and chitosan in terms of UV, FTIR, GPC and MALDI-TOF MS. Meanwhile, the structure and morphology of wool fiber grafted with chitosan were characterized by ATR-FTIR and SEM. Compared with untreated wool, this efficient method can significantly improve the dimensional stability to felting (2.53 %), wettability and dyeability of wool fabric, and can also compensate for the strength loss caused by the pretreatment. The present work provides a useful path for the enzymatic modification of keratin-containing fibers like wool using chitosan and other natural biopolymers with similar structure.