Green dyeing of modified cotton fabric with Acalypha wilkesiana leave extracts

Over the last few decades, a number of natural dyes have become non-toxic, eco-friendly and biocompatible substitutes of highly carcinogenic synthetic dyes. Herein, we selected the Acalypha wilkesiana (copper plant) as the source of a natural colorant for auxiliary-free dyeing of cotton, a way forward to eco-friendly dyeing. The bioactive phytochemical constituents of this plant include tannins, flavonoids, phlobatanins, cardiac glycosides, saponins, alkaloids, terpenes and steroids. Both the aqueous and methanol extracts of copper leaf were extracted and applied to unmodified and modified cotton fabrics with the percentage shade depths of 0.5%, 1%, 2%, 4%, 5% and 6% both at pH 4 and 7. The cationized samples rendered substantial improvement in color strength (K/S) values as compared to un-cationized ones. Aqueous and methanolic extracts offered very similar K/S values on cationized samples. Without using any metallic salts as mordants, the color fastness properties like rubbing fastness, washing fastness were also slightly improved due to greater dye fixation on cationized samples compared to uncationized ones. In conclusion, the aqueous extract exhibited dye fixation and color fastness properties comparable to methanolic extract at pH 4 and 7. Thus, it suggested the avoidance of toxic organic solvent for extraction and auxiliary chemicals in subsequent dyeing, a step towards eco-friendly sustainable dyeing. [Display omitted] •Chemical-free extraction of natural dye.•Eco-friendly dyeing of cotton with natural colorants.•Mordant-free dyeing of cotton with natural dye.•Application of natural dye through sustainable and pollution free dyeing process.