Rayon – wikipedia gas oil ratio calculator


When a solution of cellulose in cuprammonium hydroxide gas 89 comes into contact with sulfuric acid, the cellulose begins to precipitate from the solution. The sulfuric acid reacts with a complex compound of copper and dissolves it. Thin blue fibers of rayon are formed. After some time, sulfuric acid reacts with the complex compound and washes out the copper salts from the fibers. The fibers become colorless.

Since rayon is manufactured from naturally occurring polymers, it is not considered to be synthetic [1]. Technically, the term synthetic fiber is reserved for fully synthetic fibers. In manufacturing terms, rayon is classified as a fiber formed by regenerating natural materials into a usable form. [2] Specific types of rayon include viscose, modal and lyocell, each of which differs in manufacturing process and properties of the finished product.

Rayon is made from purified cellulose, harvested primarily from wood pulp, which is chemically converted into a soluble compound. It is then dissolved and forced through a spinneret to produce filaments which are chemically solidified, resulting in fibers of nearly pure cellulose. [3] Unless the chemicals are handled carefully, workers can be seriously harmed by the carbon disulfide used to manufacture most rayon. [4] [5]

Rayon should not be confused with acetate ( cellulose acetate) or triacetate. Although these terms were sometimes used interchangeably in the past, they are now distinct. The difference is that while the rayon process reconstitutes the natural cellulose polymer, the older acetate process reacts cellulose with acetic anhydride to form cellulose acetate. Furthermore, rayon production requires carbon disulfide as a solvent, while acetate uses considerably safer solvents such as acetone. Because rayon is a more robust fiber than the otherwise similar acetate, it has come to dominate the market.

Swiss chemist Matthias Eduard Schweizer (1818–1860) discovered that cellulose dissolves in tetraaminecopper dihydroxide. Max Fremery and Johann Urban developed a method to produce carbon fibers for use in light bulbs in 1897. [7] Production of cuprammonium rayon for textiles started in 1899 in the Vereinigte Glanzstoff Fabriken AG in Oberbruch near Aachen. [ citation needed] [8] Improvement by J. P. Bemberg grade 6 electricity AG in 1904 made the artificial silk a product comparable to real silk. [ citation needed] [9] Viscose method [ edit ]

English chemist Charles Frederick Cross and his collaborators, Edward John Bevan and Clayton Beadle, patented their artificial silk in 1894. They named their material viscose because its production involved the intermediacy of a highly viscous solution. The process built on the reaction of cellulose with a strong base, followed by treatment of that solution with carbon disulfide to give a xanthate derivative. The xanthate is then converted back to a cellulose fiber in a subsequent step. The first commercial viscose rayon was produced by the UK company Courtaulds Fibres in 1905. Courtaulds formed an American division, American Viscose (later known as Avtex Fibers), to produce their formulation in the United States in 1910. [10] The name rayon was adopted in 1924, with viscose being used for the viscous organic liquid used to make both rayon and cellophane. In Europe, though, the fabric itself became known as viscose, which has been ruled an acceptable alternative term for rayon by the US Federal Trade Commission (FTC). [ citation needed]

The viscose method can electricity bill nye use wood as a source of cellulose, whereas other routes to rayon require lignin-free cellulose as starting material. The use of woody sources of cellulose makes viscose cheaper, so it was traditionally used on a larger scale than the other methods. On the other hand, the viscose process affords large amounts of contaminated wastewater. Rayon was produced only as a filament fiber until the 1930s, when methods were developed to utilize broken waste rayon as staple fiber.

The Lyocell process relies on dissolution of cellulose products in a solvent, N-methylmorpholine N-oxide. The process starts with woody sources of cellulose and involves dry jet-wet spinning. It was developed at the now defunct American Enka and Courtaulds Fibres. As of 2013, Lenzing’s Tencel brand is perhaps the most widely known lyocell fiber producer. [ citation needed] Modal [ edit ]

Modal is processed under different conditions to produce a fiber that is stronger and more stable when it is wet than standard rayon, yet has a soft feel, similar to cotton. It can be tumble dried without damage due to its increased molecular alignment. [12] The fabric has been known to pill less than cotton due to fiber properties and lower surface friction. [13]

Rayon is a versatile fiber and is widely claimed to have the same comfort properties as natural fibers, although the drape and slipperiness of rayon textiles are often more like nylon. 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, although also making their hand (feel) cool and sometimes almost slimy to the touch. [14]

The durability and appearance retention of regular viscose rayon are low, especially when wet; also, rayon gasbuddy trip has the lowest elastic recovery of any fiber. However, HWM rayon (high-wet-modulus 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. [11]

• Acid Bath. As the viscose exits the spinneret, it lands in a bath of sulfuric acid, resulting in the formation of rayon filaments. The acid is used as a regenerating agent. It converts cellulose xanthate back to cellulose. The regeneration step is rapid which doesn’t allow proper orientation of cellulose molecules. So to delay the process of regeneration, zinc sulphate is used in the bath which converts cellulose xanthate to zinc cellulose xanthate thus providing time for proper orientation to take place before regeneration.

High wet modulus rayon (HWM) is a modified version of viscose that is stronger when wet. It also has the ability to be mercerized like cotton. HWM rayons are also known as polynosic. Polynosic fibers are dimensionally stable, and do not shrink or get pulled out of shape when wet like many rayons. They are also wear resistant and strong while maintaining a soft, silky feel. They are sometimes identified by the trade name Modal. [18]

Highly toxic carbon disulfide is used in the production of viscose, leading to many incidents and legal cases. [19] However, the volatile carbon disulfide is lost before the rayon gets to the consumer; the rayon itself gas engine tom is basically pure cellulose. [4] Studies from the 1930s show that 30% of American rayon workers suffered severe effects. Rates of disability in modern factories (mainly in China, Indonesia and India) are unknown. [5] [20] Disposal and biodegradability [ edit ]

Rising cotton prices in 2010 led clothing makers to begin replacing cotton with rayon in their fabrics. 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, yet rayon has a price advantage over cotton. [23] Mislabelling [ edit ]

In 2010, the U.S. Federal Trade Commission issued letters informing over 100 companies that they were mislabeling products made of rayon as being made from bamboo, deceiving environmentally conscious consumers. [24] In 2015, the FTC filed complaints against Bed Bath Beyond, Nordstrom, J.C. Penney, Backcountry.com, and their subsidiaries, for continuing to deceptively sell rayon mislabeled as bamboo. The four companies were required to pay civil penalties totaling US$1.3 million for violating the Textile Act and the Textile Rules and Section 5(m)(1)(B) of the FTC Act. [25] Similar action took place in Canada. [26] Impact on U.S. textile industry [ edit ]

Rayon contributed partly to the decline of the US textile industry in the 1920s. [27] It is far cheaper to produce than wool, cotton, or silk. It also requires less processing and hence fewer workers. In addition, it was 50% cheaper than silk during the 1920s in the US. [27] Then, it was used initially for men’s socks but later for lingerie and women’s stockings. [27] Producers [ edit ]

Bemberg is a trade name for cupramonium rayon developed by J. P. Bemberg. Bemberg performs much like viscose but has a smaller diameter and comes closest to silk in feel. Bemberg is no longer produced in Italy, but is still produced in Japan, due gas buddy to United States Environmental Protection Agency regulations in the US. The fibers are finer than viscose rayon. [9]

Modal and Tencel are widely used forms of rayon produced by Lenzing AG. Tencel, generic name lyocell, is made by a slightly different solvent recovery process, and is considered a different fiber by the US FTC. Tencel lyocell was first produced commercially by Courtaulds’ Grimsby plant in England. The process, which dissolves cellulose without a chemical reaction, was developed by Courtaulds Research.