Synergetic effect of Camellia sinensis waste extract and zinc oxide nanoparticle for improving performance and appearance attributes of viscose fabrics

Environment-friendly textile dyeing technologies are increasingly popular because of raised environmental consciousness and the need for environmentally friendly substitutes for synthetic dyes. Waste black tea is an appropriate source of polyphenols with ecological as well as functional benefits, such as protection against UV radiation, microbial resistance, and antioxidant activity. The objective of this study is to analyze the efficiency of black tea waste extract (BTWE) as a natural colorant for dyeing and functional finishing of viscose fabric. The dyeing conditions, like pH, temperature, dye concentration, and time, were systematically regulated to determine the proper conditions for maximum color strength (K/S).The colorfastness of the dyed fabric against washing, perspiration, crocking, and light were determined. The performance attributes of the dyed fabrics, viz., antimicrobial resistance and protection against UV rays, were enhanced using zinc oxide nanoparticles (ZnO-NPs).Results revealed that the optimum dyeing conditions were found to be: pH 3.0, 45°C, 4% dye, for 60 min.Finishing the dyed samples with ZnO-NPs enhanced the K/S and antimicrobial activity without negative impact on the mechanical strength. The dyed viscose fabric exhibited excellent resistance towards Gram–positive ( Staphylococcus aureus ) and Gram – negative ( Escherichia coli ) bacteria as well as the fungus Candida albicans . The antioxidant activity of the dyed samples was greatly improved compared to undyed viscose fabric. However, enhancement of the ultraviolet protection factor of the dyed fabric was limited, likely due to inadequate surface coverage and lack of coating operations. The discrepancy in the chemical and morphological structures among the undyed and the corresponding dyed viscose fabrics was monitored using Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The correlation between the different dyeing parameters and the color strength as well as the colorimetric data was assigned using analysis of variance ANOVA. The findings of this investigation justify the potential application of black tea waste as a green colorant for sustainable dyeing and functional finishingof viscose fabrics without deterioration in the fibers' weight and strength.