Natural Flavonoid-Functionalized Silk Fiber Presenting Antibacterial, Antioxidant, and UV Protection Performance

Abstract

Natural bioactive compounds as promising alternatives to synthetic finishing agents have recently gained increasing attention in the textile industry due to their eco-friendliness, low irritation, and biocompatibility. The present study reports a sustainable approach for preparing antibacterial, antioxidant, and UV-protective silk fiber using two natural flavonoids (quercetin and rutin) by an adsorption technique. The adsorption kinetics and isotherms of the two flavonoids were investigated, and their functionalities and the washing durability of their functionalities were discussed. The equilibrium adsorption isotherms fitted well to the Langmuir and Freundlich adsorption models, demonstrating that ion–ion interactions, hydrogen bonding, and van der Waals forces play major roles in the adsorption of quercetin and rutin on silk. The adsorption isotherm parameters of quercetin and rutin had a decisive effect on their adsorption kinetics, which fit well to the pseudo-second-order kinetic equation. Quercetin exhibited higher initial adsorption rate, shorter half adsorption time, and higher adsorption capability than those of rutin due to its higher affinity constant. Quercetin also imparted better antioxidant, antibacterial, and UV protection performance to silk than rutin at the same initial application concentration and provided better washing durability of functionalities. This study demonstrates that quercetin and rutin can be employed as promising multifunctional agents for the chemical processing of silk materials.