Dyeing parameters of hydroxynaphthoquinones extracted from <i style="">Arnebia</i> <i style="">nobilis</i> Rech.f

Abstract

Ratanjot (<i style="">Arnebia nobilis</i> Rech.f) has been used to extract dye for its application on various textile substrates such as cotton, wool, silk, nylon, polyester and acrylic. The sensitivity of the dye extract to <i>p</i>H and temperature is studied. The dye exhibits acute sensitivity to <i style="">p</i>H in terms of its solubility and colour. It is found to be thermally stable upto 80°C. The dyed polyester shows pink colour, nylon shows blue and all other substrates acquire a purple hue under similar dyeing conditions. This may be due to the reduction of dye from quinonoid form to benzenoid form in all the substrates except in polyester. The dye shows excellent wash, rub and perspiration fastness, however light fastness is found to be poor.