Question 54 (Textile Technology & Fibre Science)
A cotton fabric is dyed at 5 % shade (owf) using a monofunctional reactive dye. The molecular weight of the dye and cellobiose unit is 400 and 342, respectively. If all the hydroxyl groups in cellulose are accessible for reaction, the percentage of unreacted hydroxyl groups of cellulose remaining after dyeing (rounded off to 2 decimal places) is ___.
Frequently Asked Questions | FAQs
What is monofunctional reactive dye ?
A monofunctional reactive dye is a type of dye that contains a reactive group, such as a vinylsulfone or isocyanate, which can react with the fibers in a fabric to form a covalent bond. The bond is strong and resistant to washing, light, and other types of degradation, which makes monofunctional reactive dyes ideal for use in dyeing cellulosic fibers, such as cotton, linen, and rayon. These dyes can produce bright and durable colors, and they are often used in the textile industry for producing clothing, upholstery, and other textiles.
What is cellobiose ?
Cellobiose is a disaccharide sugar that is composed of two glucose molecules linked by a β(1→4) glycosidic bond. It is a breakdown product of cellulose, which is the main structural component of plant cell walls. Cellobiose is typically produced through the hydrolysis of cellulose by cellulases, which are enzymes produced by fungi, bacteria, and other microorganisms.
Cellobiose is an important substrate for the fermentation processes used in the production of biofuels and other industrial products, such as lactic acid and ethanol. Additionally, it is used as a research tool to study the physiology and genetics of microorganisms, as well as the biochemistry and enzymology of carbohydrate metabolism.