Coloration and Functionalization of Mulberry Silk Fabrics with Laccase-Catalyzed Oxidation Products of Catechin and Gallic Acid

In this work, a simultaneous coloration and functionalization process of laccase-catalyzed oxidation products (LCOPs) of catechin and gallic acid on silk fabrics was developed. The progress of the polymerization reaction leading to the formation of the polymerized product was monitored by ultraviolet–visible (UV–vis) spectroscopy. The color depth of the dyed fabrics depended on the pH of the dye bath and the temperature of the treatment conditions. The silk fabric dyed with LCOPs of catechin and gallic acid yielded maximum color strength at 50 °C (K/S = 27.53, and 24.87) and at pH 5 (K/S = 20.376 and 28.009, respectively) for 60 min. The dyed silk fabrics exhibited good UV protection properties with ultraviolet protection factor (UPF) values of 57.36 ± 5.59 and 54.53 ± 4.79, respectively, using alum mordant. The products of the laccase-catalyzed reaction of catechin and gallic acid had the potential to serve as colorants and offered an environmentally friendly approach for dyeing within the textile industry.