Vat Dyes and Their Application
نویسنده
چکیده
ong before the advent of systematic L physical sciences and the growth of the chemical industry, as long as 5000 years ago in India, dyeing methods were being used for the application of the water insoluble pigment, indigo, to natural fibers. In the early nineteenth century, between the first cotton gin and the Civil War, the value of natural indigo produced in South Carolina exceeded that of rice or cotton. Indigo was first recovered from the water soluble glucoside of indoxyl (indican) present in the plants Indigofera and Zsatis tinctoria, and then the insoluble blue product was dissolved in wooden vats by a natural fermentation process later known as vatting. This was the origin of the name vat dyes. Chemically speaking, vatting is a reduction. In the right conditions, the known animal and vegetable (cellulosic) fibers accepted the greenish-yellow material dissolved in the vat, and on subsequent exposure of the dyed fibers to the oxygen in the air, the color was converted back to that of the original indigo pigment. Restoration of the indigo is an oxidation. Both oxidation and reduction will be discussed
منابع مشابه
Sulfur Dyes and Their Application
Part 1 of this chapter covers the chemical development of sulfur dyes and the general principles of their application to cotton. Sulfur dye reduction and oxidation are compared with those of vat dyes. The effect of different chemicals on each part of the dyeing process is discussed with respect. to their cost, benefits and environmental impact.
متن کاملDyeing Wool with Metal-free Dyes – The Use of Sodium Borohydride for the Application of Vat Dyes to Wool
متن کامل
Biobleaching of Industrial Important Dyes with Peroxidase Partially Purified from Garlic
An acidic peroxidase was extracted from garlic (Allium sativum) and was partially purified threefold by ammonium sulphate precipitation, dialysis, and gel filtration chromatography using sephadex G-200. The specific activity of the enzyme increased from 4.89 U/mg after ammonium sulphate precipitation to 25.26 U/mg after gel filtration chromatography. The optimum temperature and pH of the enzyme...
متن کاملBiochemical parameters of liver function in artisans occupationally exposed to “vat dyes”
BACKGROUND Vat dyes are the class of dyes used in textile dyeing in Abeokuta, South Western Nigeria. While some dyes (including vat dyes intermediates) have been associated with adverse effects on manufacturer's health, there is paucity of data on effects of occupational exposure to vat dyes among end users, such as those involved in textile dyeing and finishing. AIMS AND OBJECTIVES To invest...
متن کاملDyeing with Disperse Dyes
Before the First World War, almost all dyes were applied from solution in an aqueous dyebath to substrates such as cotton, wool, silk and other natural fibres. However, the introduction of a man-made fibre, cellulose acetate, with its inherent hydrophobic nature, created a situation where very few of the available dyes had affinity for the new fibre. Water-soluble anionic dyes had little substa...
متن کامل