Dyeing of Wool with Anthraquinone based Natural Colorants from Cassia fistula fruit

The searches for new sources of natural dyes have been recently increased in many countries. This article is aimed to explore the dyeing potential of Cassia fistula as a source of natural dye on wool. In this study, the anthraquinone colorants are extracted from fruit of Cassia fistula by aqueous extraction method. Mordanting and subsequent dyeing of wool with extracted colorants were then performed to study the colorimetric and fastness properties. Three metallic salts aluminum sulfate, ferrous sulfate, stannous chloride and their combinations were used in this study to fix and increase the color as well as fastness properties of the substrate. UV visible and Fourier transform infrared spectroscopy (FTIR) analysis show identification of functional groups in the dye molecule. Colorimetric properties were analyzed by reflectance spectrometry in terms of L*, a*, b*, c*, h○ and K/S values. Color fastness was investigated in terms of light, wash and rub (dry/wet) tests. Results demonstrate that novel and fashionable brown shades with different hue and tone were obtained. Therefore, Cassia fistula has an exciting opportunity to be used as a source of natural dye in textile coloration.