Application of Different Non-ionic Surfactants on the Conventional Extraction and Dyeing Characteristics of Natural Dyes on the Wool Yarn

This study presents the application of three commercial non-ionic surfactants, namely nonylphenol polyethylene glycol ether (Kenon), sorbitan ester polyethylene glycol ether (Tween), and oleic acid polyethylene glycol ester (Keol), to improve the extraction process of weld, madder, and walnut green husk natural dyes. The critical micelle concentration (CMC) values of Keol, Kenon, and Tween were 0.15, 0.19, and 0.25 g/L, respectively. The introduction of non-ionic surfactants into the solution markedly improved colorant extraction from plant sources, leading to a significant increase in the percentage of dye extracted in water. The wool dyeing with extracted dyes was also found to benefit from the presence of Tween, resulting in up to 11, 29 and 28 % increase in the color strength for weld, madder and walnut green husk extracts, respectively. Moreover, non-ionic surfactants improved dyeing and levelling properties of wool samples, and did not negatively impact on the general fastness ratings of dyed samples. Overall, this study suggests that the use of non-ionic surfactants provides a favorable manner for improving the extraction process of natural dyes and enhancing their dyeing properties.