Cellulose rayon

Cellulosics. Rayon and other cellulose products such as cellophane and cellulose ethers (qv) consume 1.9% of U.S. caustic soda demand. Because of competitive products, however, this market has been decreasing since 1965 and forecasted average annual growth through 1992 is less than 0.4% (6) (see Cotton). 

Other Cellulosics. Rayon is bleached similarly to cotton but under milder conditions since the fibers are more easily damaged and since there is less colored material to bleach. Cellulose acetate and triacetate are not usually bleached. They can be bleached like rayon, except a slightly lower pH is used to prevent hydrolysis. The above fibers are most commonly bleached with hydrogen peroxide. Linen, dax, and jute requite more bleaching and mil der conditions than cotton, so multiple steps are usually used. Commonly an acidic or neutral hypochlorite solution is followed by alkaline hypochlorite, peroxide, chlorite, or permanganate, or a chlorite step is done between two peroxide steps. A one-step process with sodium chlorite and hydrogen peroxide is also used. 

Horns and hooves were the raw materials for the early polymer preparations. These materials were ground up and treated in various ways so that they could be fabricated into such items as combs to use for ladies hair, and other specialty things of that sort. The next development was the use of cellulose from cotton or from wood as the raw material which was studied for making films and fibers. Work on the cellulose structure had provided information that it was a hydroxylated product, and by converting the hydroxyls to esters, the natural cellulose could be turned into a soluble material, which was spun into fibers and cast into films to make the first cellulose rayon-type material and cellulose films. 

Regenerated proteins from casein (lanital), peanuts (ardil), soybeans (aralac), and zine (vicara) are used as specialty fibers. Regenerated and modified cellulose products, including acetate, are still widely used today and the production of fibers is similar to that described above for synthetic fiber production. Most regenerated cellulose (rayon) is produced by the viscose process where an aqueous solution of the sodium salt of cellulose xanthate is precipitated in an acid bath. The relatively weak fibers produced by this wet spinning process are stretched to produce strong rayon. 

Other Cellulosics. Rayon is bleached similarly to cotton but under milder conditions since die fibers are more easily damaged and since there is less colored material to bleach. 

Macromolecular chemistry covers a particularly wide field which includes natural polymeric material, such as proteins, cellulose, gums and natural rubber industrial derivatives of natural polymers, such as sodium carboxymethyl cellulose, rayon and vulcanised rubber and the purely synthetic polymers, such as polythene (polyethylene), Teflon (polytetrafluoroethylene), polystyrene, Perspex (poly (methyl... 

Other fibers. The other major class of synthetic fibers, the polyacrylonitriles (orlon, acrilon, etc.) like the cellulosics (rayon, cotton) show no thermal activity up to 300 °C. Above these temperatures degradation of sample accompanies any characteristic transitions or curing exotherms. To minimize this effect, the samples are run in an inert environment such as N2, as seen in figure 16. Under these conditions reproducible characteristic endotherms were obtained for identifying wool, cotton and rayon. In roughly the same temperature region,... 

The natural sodium sulfate industry in the United States in 2003 involved two producers, one in California and the other in Texas. On the byproduct manufacturing side, sodium sulfate was recovered in 17 plants across the United States these included ascorbic acid manufacture, battery reclamation, cellulose, rayon, and silica pigments. Approximate consumption of sodium sulfate by end use was soap and detergents, 46 percent pulp and paper, 13 percent textiles, 12 percent glass, 11 percent and others, 23 percent. See Table 26.6 for statistics on sodium sulfate production and consumption. 

Carbon and graphite fibers are made by the pyrolysis of certain naturally occurring and man-made fibers, such as regenerated cellulose (rayon) fibers. A wide range of physical, mechanical and chemical properties may be obtained dependent on amount of dehydration. This product is one of the most structurally efficient reinforcements. Unlike any other reinforcement, it retains its 2,800 MPa (400,000 psi) tensile strength when tested up to a temperature of 2700 C (4800F). 

It was reported that the oxidative thermal degradation of the grafted fiber depended on the amount of grafted polymer and on the structure of the cellulose substrate (cotton cellulose, rayon, etc.). 

Reinforcing carbon fibers from reconstituted cellulose (rayon) ... 

Semisynthetic cellulosics (rayon, methyl-cellulose, cellulose acetate), modified starches (starch acetate, etc.)... 

A 0-5 per cent solution of a regenerated cellulose has a fluidity of about 40, which is approaching the limit of accuracy of measurement. It is therefore usual to work with a 2 per cent solution which brings fluidities into the range of 7-5 to 35,- and normally well-bleached regenerated cellulose rayon should have a fluidity of 11 to 12. For mixtures of cotton and viscose or other chemically similar rayons, the weights of fibre required per 100 ml of cuprammonium solution are given in Table 3.2. 

The dyeing properties of the direct dyes have received more attention than those of any other group because regenerated cellulose rayons varied considerably in physical properties in their early days, and some direct dyes covered up the irregularities better than others. This led to an exhaustive endeavour to find a basis on which selection could be made. An early suggestion was Whittaker s capillary test, which graded dyes according to the... 

Austria. The Statistische Nachrichten (3), issued monthly, gives statistics on population, labor conditions, production, foreign trade, and wholesale prices. Production figures are given for caustic soda, chlorine, carbon dioxide, calcium carbide, lime-ammonium nitrate, acetylene (dissolved), oxygen, soda crystals, soaps and detergents, cellulose, rayon, and magnesite. 

Carbon disulfide s most important industrial use, however, has been in the manufacture of regenerated cellulose rayon by the viscose process (viscose rayon) and of cellophane (Davidson and Feinleib 1972 EPA 1978a NIOSH 1977 Timmerman 1978 WHO 1981). In 1974, over 80% of the carbon disulfide manufactured was used to make viscose rayon and cellophane (Austin 1974). This proportion fell to 50% in 1984, but the rayon and cellophane uses still accounted for the greatest fraction of carbon disulfide production (Mannsville Chemical Products Corp. 1985). Since 1989, the consumption of carbon disulfide in the production of carbon tetrachloride has increased to 38%, while the rayon industry s consumption has dropped to 34% (HSDB 1995). 

Carbon disulfide is used in the manufacture of regenerated cellulose rayon, cellophane, soil disinfectants, and electronic vacuum tubes. Other major uses are in the production of carbon tetrachloride, xanthates, thiocyanates, plywood adhesives, and rubber accessories. It is also used as a solvent and as an eluant for organics adsorbed on charcoal in air analysis. 

Flammability Tests Burning wool smells like burnt horn, burning silk smells like burnt egg-white, and burning cellulose fiber smells like burnt paper. Polyamide and polyester fibers melt before they burn polyacrylonitrile fibers, upon burning, leave a residue of hard, black spherical particles. On heating the dry fibers in a test tube, wool, silk, and polyamides develop alkaline vapors, while cotton, bast fibers, and regenerated cellulose (rayon) develop acidic vapors (test with moistened universal indicator paper). 

The nitration of cellulose became a base for a laige number of empirical efforts to modify cellulose. Louis Menard discovered that tetranitrated cellulose could be dissolved in a mixture of diethyl ether and ethanol (3,4). He labeled the resulting thickened liquid collodion. In the mid 1860 s, John W. Hyatt mixed collodion and camphor (S) to form a hard brittle material he called celluloid. In 1875, Allied Nobel announced the development of blasting gelatin, a combination of collodion and nitrogylcerin. A development which lead to several artificial fabrics occurred when Hilaire de Chaidoimet announced spun cellulose nitrate fabric at the Paris Exhibition in 1889 (6). The material was too flammable to be practical but lead to the development of reprecipitated cellulose, rayon, and cellulose acetate, a common fiber and plastic. 

Lichenin, cellulose rayon, intensely plasticised rubber. 

Mesocolloidal (pol. degree 100—500) Normally plasticised rubber, native balata, and gutta percha i -cellulose, rayon, cellophane-foil Pepsin Insulin i ditto, in the solid state sometimes rubbery Shellac (probably), somewhat polymerised damar and copal. Phenol- or urea-formaldehyde between the A-and B-stages. 

The chemical industry s interest in polymers dates back to the 19th century. In those days it was a case of synthetically modifying natural polymers with chemical reagents to either improve their properties or produce new materials with desirable characteristics. Notable examples were nitration of cellulose giving the explosive nitrocellulose, production of regenerated cellulose (rayon or artificial silk) via its xanthate derivative, and vulcanization of rubber by heating with sulphur. Manufacture of acetylated cellulose (cellulose acetate or acetate rayon) developed rapidly from 1914 onwards with its use both as a semi-synthetic fibre and as a thermoplastic material for extrusion as a film. 

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