Abstract

Natural dyes extracted from fresh Tectona grandis (Teak tree) leaves as one of the Non-Wood Forest Products (NWFPs) using 50 % ethanol as solvents has been utilized for dyeing of cotton fabric with or without mordants. Simultaneous mordanting method using mordants such as alum, CuSO4 and K2Cr2O7 of various concentrations (1-2 %) was employed during the dyeing of scoured cotton fabrics and stability of colour on the dyed fabrics were determined in terms of light, wash and rub colour fastness. The dye extract was characterized using ultraviolet-visible (UV- Vis) and Fourier transform infrared (FTIR) spectroscopy. The applicability of the dye extract as PH indicator in acid-base titration was also studied. UV-Vis absorption spectra indicates maximum wavelength at -- nm and structural characterization by FTIR revealed among other functional groups the presence of C=O, O-H and C=C of aromatic compound. The end points obtained using the natural dye extract from Tectona grandis leaves in acid-base titration involving HCl and CH3COOH as acids and NaOH and NH4OH as bases are comparable to synthetic indicators (Phenolphthalein and Methyl orange) used. Mordanting was found to improve the dyeing properties of the fabrics and can be utilized in eco-friendly textile dyeing and as replacement for synthetic indicators that are carcinogenic.