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Rayon

Rayon. Rayon.

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Rayon

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  1. Rayon

  2. Rayon Rayon is a manufactured regenerated cellulose fiber. Because it is produced from naturally occurring polymers, it is neither a truly synthetic fiber nor a natural fiber; it is a semi-synthetic or artificial fiber. Rayon is known by the names viscose rayon and art silk in the textile industry. It usually has a high luster quality giving it a bright sheen.

  3. Index • Uses • History • Production method • Major Properties • Alternative to cotton • Picture Gallery

  4. Uses Some major rayon fiber uses include apparel (e.g. Aloha shirts, blouses, dresses, jackets, lingerie, linings, scarves, suits, neckties, hats, socks), the filling in Zippo lighters, furnishings (e.g. bedspreads,bed sheets, blankets, window treatments, upholstery, slipcovers), industrial uses (e.g. medical surgery products, non-woven products, tire cord), and other uses (e.g. yarn, feminine hygiene products, diapers, towels). Rayon is a major feedstock in the production of carbon fiber

  5. History The invention of rayon can be related to the invention of an apparatus in 1840 that drew synthetic filaments through small holes. In 1855, Georges Audemars, a Swiss chemist, discovered how to make cellulose nitrate. Later in 1884, Count Hilaire de Chardonnet made the first man made fibers from nitrocellulose. He came to be known as the 'father of rayon'. He got the original French patent and also won financial support through which, he established the world's first rayon factory. Subsequently, other scientists developed more cost-effective ways of making many other types of rayon. 

  6. Production method • Cellulose: Production begins with processed cellulose • Immersion: The cellulose is dissolved in caustic soda: (C6H10O5)n + nNaOH → (C6H9O4ONa)n + nH2O • Pressing: The solution is then pressed between rollers to remove excess liquid • White Crumb: The pressed sheets are crumbled or shredded to produce what is known as "white crumb“ • Aging: The "white crumb" is aged through exposure to oxygen • Xanthation: The aged "white crumb" is mixed with carbon disulfide in a process known as Xanthation, the aged alkali cellulose crumbs are placed in vats and are allowed to react with carbon disulfide under controlled temperature (20 to 30 °C) to form cellulose xanthate: (C6H9O4ONa)n + nCS2 → (C6H9O4O-SC-SNa)n • Yellow Crumb: Xanthation changes the chemical makeup of the cellulose mixture and the resulting product is now called "yellow crumb"

  7. Viscose: The "yellow crumb" is dissolved in a caustic solution to form viscose • Ripening: The viscose is set to stand for a period of time, allowing it to ripen: (C6H9O4O-SC-SNa)n + nH2O → (C6H10O5)n + nCS2 + nNaOH • Filtering: After ripening, the viscose is filtered to remove any undissolved particles • Degassing: Any bubbles of air are pressed from the viscose in a degassing process • Extruding: The viscose solution is extruded through a spinneret, which resembles a shower head with many small holes • Acid Bath: As the viscose exits the spinneret, it lands in a bath of sulfuric acid, resulting in the formation of rayon filaments: (C6H9O4O-SC-SNa)n + ½nH2SO4 → (C6H10O5)n + nCS2 + ½nNa2SO4 • Drawing: The rayon filaments are stretched, known as drawing, to straighten out the fibers • Washing: The fibers are then washed to remove any residual chemicals • Cutting: If filament fibers are desired the process ends here. The filaments are cut down when producing staple fibers.

  8. Major properties Rayon is a versatile fiber and has the same comfort properties as natural fibers. It can imitate the feel and texture of silk, wool, cotton and linen. The fibers are easily dyed in a wide range of colors. Rayon fabrics are soft, smooth, cool, comfortable, and highly absorbent, but they do not insulate body heat, making them ideal for use in hot and humid climates. The durability and appearance retention of regular viscose rayon are low, especially when wet; also, rayon has the lowest elastic recovery of any fiber. However, HWM rayon is much stronger and exhibits higher durability and appearance retention. Recommended care for regular viscose rayon is dry-cleaning only. HWM rayon can be machine washed.

  9. Alternative to cotton Rising cotton prices in 2010 led clothing makers to begin replacing cotton with rayon in their fabrics. Designers such as Isaac Mizrahi have incorporated rayon into their newest designs. As demand for rayon increases, companies such as Fortress Paper have been investing in pulp mills to increase production. Rayon now sells for as much as $2.70 per pound, which has led to an increase in the retail price of clothing made with rayon, despite rayon's price advantage over cotton

  10. Picture gallery

  11. MADE BY – UditKalra VIII-A 30

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