Comparative properties of pure and sulphonated dyes extracted from henna (<i>lawsonia inermis</i> (linnaeus) and kolanut (<i>cola nitida</i> (vert.) Schott & endl.) Plants

Abstract

In continuation of our research on the extraction and application of plants, we report the results of the dyeing and fastness properties of dyes extracted from the leaves of Henna and Kolanut plants in chrome-tanned (Wet- Blue) leather. Dyes were extracted from Henna (Lawsonia inermis) and Kolanut (Cola nitida) plants using chloroform and acetone as solvents. The extracted dyes were subsequently sulphonated with chlorosulphonic acid. Both the extracted and sulphonated dyes were applied on chrome-tanned leather using 2% and liquor-togood ratio of 50:1 dyeing conditions and the dyeing properties (exhaustion, fixation, glazing, levelness, migration and penetration) assessed. The light, wash and rub fastness properties of the dyeings were investigated. From the results, the λ_max values of the crude dyes were found to be higher than those of the sulphonated derivative dyes in all the three solvents. The dyeing properties of Henna dyes were found to be higher than those of Kolanut dyes, with the sulphonated dyes being better than the crude extracts for both plants. Exhaustion, fixation, and migration properties of all the dyes are very good, while bleeding, glazing, levelness, and penetration of the dyes are, on the average, good. Exhaustion range from 52.23% for crude Kolanut dye to 85.04% for sulphonated Henna dye, fixation range from 50.72% for crude Kolanut dye to 63.32% for sulphonated Henna dye and migration range from 48.85% for crude Kolanut dye to 82.33% for sulphonated Henna dye. The fastness ratings of the sulphonated dyes were found to be higher than those of the crude dyes, suggesting that sulphonation has increased the affinity and substantivity of the crude dyes to leather.

Keywords: Affinity, Chrome Tanning, Dye Migration, Leather, Substantivity