Cellulose fiber production

Lanes, S.F., Cohen, A., Rothman, K.J., Dreyer, N.A. Soden, K.J. (1990) Mortality of cellulose fiber production workers. Scand. J. Work Environ. Health, 16, 247-251... 

Davidson, G., et al. H.E Rippey C.N. Cone I.F. Laucks H.P. Banks. Cellulose-Fiber Product Treated With a Size Embodying Soybean Flour and Process of Making the Same. U.S. Patent 1,622,496 (1927). 

A polymer is generally dissolved in a solvent to enable its manipulation into a usable, profitable, and marketable product. Hence, dissolution per se, is not the ultimate objective. In addition to rendering the polymer soluble, the resulting solution must have certain desirable characteristics, such as chemical and thermal stability, proper viscoelastic properties, environmental friendliness, and a general ease of manipulation, including ease of recovery. The first five solvents discussed exhibit some of these desirable characteristics. The steam explosion process is mentioned more for completeness than as a potential contender in the cellulose fiber production market. 

The SEM pictures fi om Figure 9.12A-D show the nano- to mesoscale structure of the aerogel filaments. In Figure 9.12A, a part of a fiber s surface is flaked off. The fibers exhibit the typical mantle-core stracture and are well known from cellulose fiber production [31],... 

Synthetic fiber production is the principal driving force behind the decline in cellulosic fiber production. Industrial polymerization processes provide a much greater variety of fiber-forming materials with a lower requirement for process control. In the period from 1982 to 2002, manufectured fiber production increased by 155 percent, with the rise attributed to synthetic fiber as the production of cellulosic fiber decreased. Fibers from synthetic materials account for 94 percent of total global fiber production. 

There are undoubtedly numerous chemical pre-treatment methods used in the literature for the isolation of cellulose fibers from different lignocellulosic sources. The choice of these chemical treatment methods is influenced by the properties of lignocellulosic materials such as their chemical composition, internal fiber stmc-ture, microfibril structure, microfibril angle, cell dimensions and the defects which are in return influenced by the type and the sources of the lignocellulosic materials (Siqueira et al., 2010). The intended use of the cellulosic fiber product could also have an influence on the choice of chemical treatment method (Dufresne et al., 2008). The schematic diagram showing different pre-treatment methods during cellulose isolation are depicted in (Fig 3.11). 

By 1941, as the first synthetic polymers were being converted into fibers (nylon and later polyester), regenerated cellulosic fiber production had risen to 1,250,000 ton. It continued to expand into the 1970s recording its highest ever annual output at 3,856,000 ton in 1973. Since then a steady decline has occurred as more and more end uses switch to the cheaper S5mthetic fibers based on oil valued at little more than the costs of extraction. 

Approximately 3 million metric tons of regenerated cellulose fibers production capacity existed in 2000 (Table 2). The leading producers of filament yams were the Chinese state-owned factories (118,000-t capacity), Acordis in Europe (69,0001), and the Russian plants (with 44,000 t). The leading producers of staple fiber and tow were the Chinese with 480,0001, the Birla Group (India) with 408,0001, Lenz-ing (Austria, U.S.A., and Indonesia) with 315,000 t and Acordis with 170,000-t capacity split between the United Kingdom and North America, Formosa Chemicals and Fibers Co. with 162,000 t (in Taiwan). Acordis was formed in 1998 from the fiber businesses of Courtaulds and Akzo-Nobel following the takeover of Cour-taulds by Akzo, who later sold Acordis to a consortium of CVC Partners and Acordis management. (Note since these statistics were compiled, 100,000 ton of Acordis s viscose staple fiber capacity has closed.)... 

It is shown in Table 7.6 how synthetic man-made fibers are replacing the viscose and acetate rayons produced fiom natural cotton fibers or wood pulp. During 1970 the production of cellulose fibers was 43% of world fiber output, but by 2000 the proportion had fallen to only 8%. Cellulose fiber production fell fiom 3.6 to less than 2.5 million tormes dttring the same period. Polyester fiber dorrrirtates the market and far exceeds the use of rtylon 66, rtylon 6, arrd acrylic fibers. In 1993 man-made syrrlhetic fiber production was about 17.5 rrtillion tormes while man-made celltrlose fiber production was about 2.5 million tormes. At the same time about 15.5 milUon tormes of natural cotton was rrsed. ... 

Among various derivative methods, the viscose process, invented by Cross, Bevan and Beadle in 1892, still is dominating in commercial cellulose fiber production with an armrral prodnction of more than 2 million tons. Figirre 10.4 shows the flow chart of the viscose process. The viscose process begins with the alkalization step, where the cellttlose ptrlp is treated with an 18-20 % solution of NaOH... 

Table 1. 1990 World Production of Regenerated Cellulose Fibers...

Again, irrespective of the hardware the chemistry is consistent. The partially regenerated fiber from the spinning machine is contaminated with sulfuric acid, 2inc sulfate, sodium sulfate, carbon disulfide, and the numerous incompletely decomposed by-products of the xanthation reactions. The washing and drying systems must yield a pure cellulose fiber, suitably lubricated for the end use, and dried to a moisture level of around 10%. 

Natural Products. Many natural products, eg, sugars, starches, and cellulose, contain hydroxyl groups that react with propylene oxide. Base-cataly2ed reactions yield propylene glycol monoethers and poly(propylene glycol) ethers (61—64). Reaction with fatty acids results ia a mixture of mono- and diesters (65). Cellulose fibers, eg, cotton (qv), have been treated with propylene oxide (66—68). 

Fractionation separates fines and short, weak cellulose fibers from longer, stronger cellulose fibers (52). Its primary appHcation is ia processiag old cormgated coataiaers iato aew packagiag products. 

The principal chemical iadustry based on wood is pulp and paper. In 1995, 114.5 x 10 metric tons of wood were converted iato - 60 x 10 metric tons of fiber products ranging from newsptint to pure cellulose ia the United States (1,76). Pure cellulose is the raw material for a number of products, eg, rayon, cellulose acetate film base, cellulose nitrate explosives, cellophane, celluloid, carboxymethylceUulose, and chemically modified ceUulosic material. 

Considerable effort has been devoted to finding alternative fibers or minerals to replace asbestos fibers ia their appHcations. Such efforts have been motivated by various reasons, typically, avadabihty and cost, and more recendy, health concerns. During Wodd War I, some countries lost access to asbestos fiber suppHes and had to develop substitute materials. Also, ia the production of fiber reiaforced cement products, many developiug countries focused on alternatives to asbestos fibers, ia particular on cellulose fibers readily available locally at minimal cost. Siace the 1980s however, systematic research has been pursued ia several iudustrialized countries to replace asbestos fibers ia all of their current appHcations because of perceived health risks. 

Tensile strength of the fibers is also determined by the refinement of the fiber [14] (Fig. 4). Hydrophilic properties are a major problem for all cellulose fibers. The moisture content of the fibers amounts to 10 wt% at standard atmosphere. Their hydrophilic behavior influences the properties of the fiber itself (Table 3) as well as the properties of the composite at production [15]. 

Extruded composites of plasticized PVC and short cellulose fibers have been investigated by Goettler [103]. Pronounced increases in tensile modulus, yield, and ultimate tensile strength are observed. Single step processing of reinforcement and polymer with good product performance are key characteristics of the material whose field of application lies in the vinyl hose industry. 

The pulp and paper industry produces primary products—commodity grades of wood pulp, printing and writing papers, sanitary tissue, industrial-type papers, containerboard, and boxboard— using cellulose fiber. The two steps involved are pulping and paper or paperboard manufacturing. 

Simply put, paper is manufactured by applying a watery suspension of cellulose fibers to a screen that allows the water to drain and leaves the fibrous particles behind in a web. Most modem paper products contain nonfibrous additives, but otherwise they fall within this general definition. Only a few paper products for specialized uses are created without the use of water, using dry forming techniques. The production of pulp is the major source of environmental impacts from the pulp and paper industry. 

Viscose Also known as the Cross-Bevan-Beadle process. A process for making regenerated cellulose fibers. The product has been known by the generic name rayon since 1924. Cellulose, from cotton or wood, is first reacted with sodium hydroxide ( mercerization), yielding alkali cellulose. This is dissolved in carbon disulfide, yielding cellulose xanthate, which is dissolved in sodium hydroxide solution. Injection of this solution (known as viscose... 

China. See also People s Republic of China acrylic fiber production in, 11.T89, 220 adhesive joint ventures, 1 526 advanced materials research, 1 696 aquaculture history, 3 183 aquaculture production, 3 189t ascorbic acid synthesis in, 25 754 demand for oil in, 23 530 nanocomposite development, 1 717 natural graphite in, 12 780 oil recovery program in, 23 534 olefin fiber production in, 11 243 production and consumption of regenerated cellulose fibers in,... 

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