Multifunctional Dyeing of Textiles with Turmeric (Curcuma longa L.) Extracts Using Natural Mordants.

Driven by concerns over environmental and human well-being, plant-based dyes have gained renewed attention as bio-based alternatives in textile coloration. Turmeric (the root of Curcuma longa L.) is a classical plant dye used extensively worldwide; however, it has relatively poor color fastness and limited availability, and its application in textiles requires optimization of dyeing parameters. In this study, the pigment composition of turmeric extracts was characterized by ultraviolet-visible (UV-Vis) spectroscopy, the fabrics were detected via SEM, and extraction and dyeing conditions were optimized through an orthogonal experimental design. To evaluate the impact of mordant type on the functional performance of turmeric-dyed fabrics, we compared natural and metallic mordants. This comparison was based on a comprehensive set of properties, including color depth (K/S values), chromatic parameters, color fastness, anti-ultraviolet, antioxidant capacity, and antimicrobial activity. The primary pigment component of turmeric extracts was curcumin, whose extraction was optimal at a material-to-liquor ratio of 1:8, using an 80% ethanol solution heated to 80 °C for 140 min. The ideal dyeing cotton conditions were pH 8, 70 °C, for 100 min. The application of natural mordants improved the color performances, UV protection, and antimicrobial performances of dyed samples but resulted in slightly inferior antioxidant activity compared to metallic mordants. The color fastness of dyed samples under mordants rose from moderate to excellent, apart from washing. This research highlights that turmeric-dyed natural fabrics with natural mordants could be a less hazardous option for eco-friendly textile production, providing both practical dyeing and functional properties.