Coloration of polyester fiber with natural dye henna (Lawsonia inermis L.) without using mordant: a new approach towards a cleaner production

The demand of natural colorants for the dyeing of textile fibers has been increasing gradually in recent years due to a growing global ecological awareness as well as a greater emphasis on a cleaner and greener production process. The eco-friendly dyeing of polyester fiber with natural dye henna is a novel approach that has extensively been studied in this article. To this end, the dyeing of polyester fiber with henna dye was conducted at different temperatures without using hazardous metallic mordants. Then the dyeing performance was investigated in terms of depth of shade measurement, analysis of colorimetric properties of color and assessment of color fastness properties of henna dyed polyester fabric samples. The amount of dye absorption by fiber and the resulting depth of shade were found to increase with increasing dyeing temperature. In case of colorfastness properties, all dyed substrates demonstrated excellent fastness ratings against washing, rubbing and perspiration with little to no deterioration of color. Moreover, the detailed morphological study revealed that surface structure of fiber remained unchanged after dyeing at an elevated temperature and pressure. So, the findings suggest that dyeing of polyester fiber with henna dye without any metallic mordants is a promising approach to get the desired dyeing performance alongside opening up an avenue for eco-friendly dyeing.