Rayon fiber Cuprammonium

Natural polymers can be made into hbers through dissolution of the polymer in an appropriate solvent and then extmsion of the polymer solution into a coagulation bath. As an example, cellulose can be made into viscose rayon fibers, cuprammonium rayon, cellulose acetate and triacetate fibers, lyocell, and modal fibers depending on the processes used to make the fibers. Other natural polymers such as mbber, chitosan, alginic acid, and protein can also be made into fibers in an appropriate fiber-forming process. 

A) Irradiance to a reactor was limited because the rectangular shape of the reactor contained cuprammonium rayon fiber and was made of glass for two flat sides and stainless steel for the edges. 

Fig. 12.8. Cross-sectional morphologies of some of the rayon fibers, (a) High wet modulus (b) regular rayon (c) crimped HWM (d) hollow (e) cuprammonium (f) trilobal. (Sources All except trilobah Turbak, A., "Rayon" in Encyclopedia of Polymer Science and Engineering, 2nd ed., Vol. 14, p. 55, copyright John Wiley Sons, Inc., New York, 1985 and used with permission of the copyright owner trilobal photo Gupta, B. S. and Hong, C.T., INJ, 7(1), 38 (1995).)...

In the original process, the cellulose nitrate itself was used as the fiber (hence its satirical description as mother-in-law silk ). The regenerating agent is ammonium hydrosulfide. The basic process was first demonstrated by J.W. Swan in London in 1885 but commercialized by Count L.M.H.B. de Chardonnet ( Father of the rayon industry ) in France in 1891 and operated there until 1934. The last working factory, in Brazil, burned down in 1949. The other processes for making rayon fibers by regenerating cellulose ( viscose, cuprammonium) gave superior products. See also Rayon. 

Cellulose acetate monofilament, yarn, staple, or tow Cellulose fibers, manmade Cigarette tow, cellulosic fiber Cuprammonium fibers Fibers, rayon Horeshair, artificial rayon Nitrocellulose fibers Rayon primary products fibers, straw, strips, and yarn... 

The acetate rayons are more resistant than the viscose or cuprammonium. Fiber 40 (FMC Corp.) is a type of rayon called Avril, made by a special pulping process that decreases the tendency to shrink when the fiber is wet. Avlin Fabray (Steamess Technical Textiles Co.) is a thin, lightweight, porous, nonwoven fabric of rayon fiber used for throw-away garments. 

Production of viscose rayon and cuprammonium rayon will be described as they are among the oldest wet-spun man-made fibers. 

Asahi Chemical Industries (ACl, Japan) are now the leading producers of cuprammonium rayon. In 1990 they made 28,000 t/yr of filament and spunbond nonwoven from cotton ceUulose (65). Their continuing success with a process which has suffered intense competition from the cheaper viscose and synthetic fibers owes much to their developments of high speed spinning technology and of efficient copper recovery systems. Bemberg SpA in Italy, the only other producer of cuprammonium textile fibers, was making about 2000 t of filament yam in 1990. 

Viscose rayon is but one variety of rayon, a more general term for derivatized or reconstituted cellulose. Other rayons include fiber prepared from collodion, cellulose acetate, and cellulose fiber regenerated from a cellulose-copper ammonium solution cuprammonium rayon) (Kauffman 1993). 

R. sphaeroides E15-1 was obtained from Bae et al(14). It was cultured with 12g of hydrophilic cuprammonium rayon hollow fibers (15) (diameter x length, 180 urn x 3cm) in the modified Ormerod media (16) for 2 months at 30-32°C under 154 pM photon m sec 1 irradiance using tungsten halogen lamps. Culture media was changed every week and flushed with oxygen-free argon. 

Establishments primarily engaged in manufacturing cellulosic fibers (including cellulose acetate and regenerated cellulose such as rayon by the viscose or cuprammonium process) in the form of monofilament, yarn, staple, or tow suitable for further manufacturing on spindles, looms, knitting machines, or other textile processing equipment. 

A 250 X 33 mm AM-40M-SD cartridge with hydrophilic cuprammonium rayon hollow fibers (Asahi Medical Co., Ltd, Japan). The total surface area of the 180-pm-diameter hollow fibers was 0.8 m, and the cartridge volume outside the fibers was 48 mL. 

Fig. 3 Scanning electron microscopy of Rubrivivax gelatinosus CBS immobilized on cuprammonium rayon hollow fiber (AM-40M-SD)...

In 1937, Schweizer [91] discovered that cellulosic fibers such as cotton and hemp readily dissolve in copper hydroxide and ammonium hydroxide solutions. His system is recognized as the Schweizer reagent. The Bemberg Rayon Industry later utilized this solvent for the industrial production of cuprammonium fibers (or cuprammonium rayon) and developed the Bemberg process or cuprammonium process [92]. Kamide and Nishiyama [93] have recently published an excellent review on the history and science of cuprammonium technology. 

In 1920, the Tubize Company built a plant to produce the yarn in the United States. By 1934, however, other types of superior rayon had been developed, so the nitrocellulose plant was sold to a company in Brazil. Several incidents of explosions and fires caused by the incompletely denitrated cellulose resulted in setbacks to the Chardonnet silk process, but, fortunately, the simultaneous development of cuprammonium and viscose solutions for spinning rayon rapidly replaced the more dangerous nitrocellulose fibers. 

The name rayon was officially adopted in 1924 by the National Retail Dry Goods Association. Prior to this, the fiber was called artificial silk, wood-silk, or viscose silk. On October 26, 1937, the Federal Trade Commission (FTC) officially defined rayon as a textile fiber or yarn produced chemically from cellulose or with a cellulose base. This definition covered cuprammonium and viscose rayon as well as acetate fiber. To avoid confusion in the trade, FTC rules were adopted on December 11, 1951, which defined rayon as man-made textile fibers and filaments composed of regenerated cellulose. A separate definition was adopted for acetate, man-made textile fibers and filaments composed of cellulose acetate. ... 

The properties of cuprammonium rayon are sufficiently different from those of viscose rayon that today it is produced as a specialty fiber for several applications. Apart from its use as a substitute for silk in scarves, ties, fine dresses, and linings, the use of hollow cuprammonium fibers for hemodialysis in artificial kidneys has become important. 

Continuous-filament (regular) rayon is produced by either the cuprammonium or viscose process. Both are supplied as yarn having a high sheen resembling silk. End uses include those applications where durability and dimensional stability are not particularly important. Cuprammonium fibers can be spun in finer deniers than viscose fibers, and they find a market for ladies shawls, scarves, blouses, coat linings, etc. The amount of cuprammonium fiber produced is quite small relative to viscose rayon. 

In another process, cellulose is dissolved in ammoniacal cupric hydroxide (Cu(NH3>4(OH)2). The solution is then spun as a fiber into a dilute sulfuric acid solution to regenerate the cellulose. The product is called Cuprammonium rayon. The material may still be manufactured on a limited scale. 

In 1924, the name rayon was adopted but, it did include other cellulosic products such as cuprammonium and acetate fibers and the definition was subsequently amended in 1951 to man-made textile fibers and filaments composed of regenerated cellulose. 

Figure 1 shows a electron micrograph of a cuprammonium rayon hollow fiber made by wet spinning. The sample was prepared by fixing the network structure just after coagulation to maintain it in a condition similar to the wet state. We can see a fine network in Figure 1. This fine network cannot be seen after drying the hollow fiber, presumably because of contraction. However, the fine network reappears when the dry hollow fiber is swollen by water as shown in Figure 2. The network of the membrane once dried and then swollen in water becones somewhat smaller than the original. The properties of membranes for artificial kidneys depend strongly on this fine network structure.

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