Textile Application of Natural Dye Extracted from Myrobalan (Terminalia chebula): Process Optimisation using RSM

Myrobalan is a natural dye extracted from the fruits of Terminalia chebula, a medicinal plant widely used in Ayurveda. Myrobalan has been used in textile dyeing since ancient times, as it imparts a yellowish-brown colour. It is also used as a mordant, enhancing the fixation, colour fastness, and hue of other natural dyes. Despite being the most widely used bio- mordant for dyeing with natural dyes, inconsistency in terms of dyeing method and uniform colour uptake have been a major problem in commercial dyeing using myrobalan. In this study, response surface methodology (RSM) has been used to compare the application of myrobalan on 100% cotton cambric fabric by three techniques, viz. exhaustion technique, padding technique and soaking technique. The factors studied were dye concentration, dyeing temperature, and dyeing duration. The responses measured were uniformity of colour uptake, colour strength (K/S), colour coordinates (L*a*b*), and fastness properties (washing and rubbing). The results show that the optimal technique for uniform dyeing using myrobalan is the padding technique, employing 3 nip-dips of 20% owf dye liquor, at a dyeing temperature of 50oC. This technique produces the desired colour, while reducing dyeing time and water consumption, as compared to the conventional exhaustion technique. The optimized technique of myrobalan dyeing is promising for sustainable natural dyeing in commercial sector.