Cleaner Sustainable Route to Develop UV Protective and Colorful Wool Yarns: Natural Flavonoid-based Colorants from Millettia Laurentti Sawdust

Synthetic dyes have gained much of the textile dyeing market by offering various colors. Synthetic dyes have been a worry for the environment owing to their hazardous nature running in parallel. In recent decades, there has been a movement to substitute natural compounds due to their biocompatibility, biodegradability, and biological advantages. This study investigated using Millettia Laurentii sawdust as a natural colorant source. Eco-friendly metal salts (aluminium sulfate, ferrous sulfate, and copper sulfate) under ecologically permitted concentration levels and biomordants (tannic acid, pine bark, oak fruit hull, and eucalyptus leaves) were used to broaden the color range (CIEL*a*b*C*ho and K/S) with significant improvements in the fastness attributes (washing, rubbing, and light) and UV protection properties. Fastness results were found in the commercially acceptable range. All the metal salts provided enhanced color yields with a maximum performance by iron and the corresponding iron-biomordant combinations (iron/pine bark and iron/oak fruit hull). Among the biomordants, pine bark extract provided better performance and higher color depth (9.16) than other biomordants. The findings of this research work showed a significant influence of metal salts and biomordants in combination with Millettia Laurentii sawdust (supposed to be a waste) for enhancing the color characteristics and functional attributes of wool yarns.