Dyeing ability of C. longa L. and T. stans (L.) Juss. Ex Kunth on unmordanted and mordanted silk and cotton fabrics

Abstract

The work was on the extraction of both the C. longa rhizomes and the petals of T. stans using four different solvents (ethanol, ethyl acetate, water, and n-hexane). The dyeing potential of the C. longa and T. stans extracts was evaluated on cotton and silk fabrics without or with mordants using potash alum, phosphomolybdic acid, iron (II) sulphate, and tartaric acid at varied temperatures and tested for colour fastness properties (wash and light fastness). The pH and absorbance of the dye bath before and after dyeing were studied. However, cotton, which is cellulosic, was better dyed than silk, which is proteinous, which showed a better choice for fabrics dyeing at 80 °C; hence, it had a good colour efficiency. Iron (II) sulphate exhibited complexes in the octahedral configuration of the coordination six with CH₂O- of cotton and NH₃⁺ and COO^- of silk fabric. In addition, it was also observed that the higher the dyeing temperature, the greater the dyeing intensity. The spectroscopic characterization of the extracts was determined with the help of UV-Vis and FTIR. The UV-Vis and FTIR spectral analyses revealed the chromophore, auxochrome groups, and functional groups, respectively, within the extracts. Curcumin and rutin were identified as being responsible for the dyeing of the fabric.