Materials cellulosic

Shinohara and Tanzawa examined the effect of orientation on the dynamic properties of viscose rayon films and fibres. (Only an abstract of their studies appears to be available in English.) Making the assumption that the structure was polycrystalline they deduced a relation between extensional and shear moduli in terms of an orientation factor tan d for each modulus was found to be independent of orientation. 

The extensional moduli parallel and perpendicular to the stretch direction of drawn films of cellulose acetate were measured by Wilson. Experiments were performed at 20°C for relative humidities of 65% and 100%. In each case the parallel modulus ( o) increased markedly with draw ratio while 90 showed a slight decrease. 

At the present time it seems possible that for non-crystalline polymers the observed mechanical anisotropy is consistent with a network deformation process, but detailed understanding awaits further evidence on possible supermolecular structure occurring in such materials. 

Cold drawn semi-crystalline polymers are characterised generally by oriented unordered fractions, through which pass strained intercrystallite 

Annealing and hot drawing have the effect of relaxing the material between crystallites, and frequently a clear lamellar structure is produced. When this occurs mechanical properties are sensitive to the lamellar geometry, and a full understanding is dependent on more detailed knowledge of lamellar structure. 

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A. Grobe, Properties of Cellulose Materials, Polymer Handbook, 3rd ed., John Wiley Sons, Inc., New York, 1989, pp. 117—170. 

Antimony Oxide as a Primary Flame Retardant. Antimony oxide behaves as a condensed-phase flame retardant in cellulosic materials (2). It can be appHed by impregnating a fabric with a soluble antimony salt followed by a second treatment that precipitates antimony oxide in the fibers. When the treated fabric is exposed to a flame, the oxide reacts with the hydroxyl groups of the cellulose (qv) causing them to decompose endothermically. The decomposition products, water and char, cool the flame reactions while slowing the production and volatilization of flammable decomposition products (see Flaa retardants for textiles). 

Therefore a fully substituted derivative would have a degree of substitution of 3.0 whilst a cellulosic material in which on average 1.8 hydroxyl groups per glucose unit had been replaced would have a degree of substitution of 1.8. Commercial derivatives usually have a degree of substitution of less than 3.0, the actual value chosen being determined by the end-use. 

In a typical process 12001b (545 kg) of the mixed acids are run into the reaction vessel and 301b (13.5 kg) of the dried cotton linters are added. The mixture is agitated by a pair of contra-rotating stirrers and nitration is allowed to proceed at about 35-40°C for 20 minutes. It is interesting to note that the cellulosic material retains its fibrous form throughout the nitration process. 

Regenerated cellulose foil has been extensively and successfully used as a wrapping material, particularly in the food and tobacco industries. Like other cellulose materials it is now having to face the challenge of the completely synthetic polymers. Although the foil has been able to compete in the past, the... 

The author is unaware of any commerical polymers that are specifically designed to degrade oxidatively, although oxidation may be involved in association with hydrolytic and biological degradation. It may be of interest to note that before World War II products known as rubbones were produced by degrading natural rubber with cobalt linoleate in the presence of cellulosic materials to produce low molecular weight, fluid oxidised natural rubber (Section 30.4). 

Cellulosic materials, such as wood, in their different forms (i.e., wood flour and wood pulp), cotton, shell flours, ground com cobs, and other vegetable by-products or agro-wastes are used as the source of cellulosic raw materials for the plastic industry [29,56], at least as... 

Processes have been developed in North America to pilot scale growing the bacterium Cellulomonas or the fungus Trichoderma on pre-treated milled cellulosic material in conventional fermentors, ie in a liquid medium. However, preparation costs are considerably higher than with solid-substrate fermentations. 

While it would be difficult to enumerate all of the efforts in the area of implants where plastics are involved, some of the significant ones are (1) the implanted pacemaker, (2) the surgical prosthesis devices to replace lost limbs, (3) the use of plastic tubing to support damaged blood vessels, and (4) the work with the portable artificial kidney. The kidney application illustrates an area where more than the mechanical characteristics of the plastics are used. The kidney machine consists of large areas of a semi-permeable membrane, a cellulosic material in some machines, where the kidney toxins are removed from the body fluids by dialysis based on the semi-permeable characteristics of the plastic membrane. A number of other plastics are continually under study for use in this area, but the basic unit is a device to circulate the body fluid through the dialysis device to separate toxic substances from the blood. The mechanical aspects of the problem are minor but do involve supports for the large amount of membrane required. 

Nitromatweed (Matweed Nitrate, Nitrosparte in Fr). Prepd by nitration of dried matweed with mixed nitric-sulfuric acids in a manner similar to the prepn of NC. Trench, Faure and MacKie (Ref 2), in 1876, patented expls containing as a base nitrosparte (or other nitrated cellulosic material such as cotton, hay, agave, hemp, flax, straw, aloe, yucca, etc) together with resin, ozokerite, collodion, glycerin, charcoal and soot. Hengst (Ref 3), in 1898, patented a smokeless powd containing nitrosparte prepd by nitration of fibers covering the coconut shell Refs 1) Merriam Webster s Diet, 2nd Ed (1963), ... 

Nordenfelt and Meurling Powder. A propint, patented in Engl in 1884, prepd as follows Cotton or other cellulosic material, was transformed into a material resembling hydrocellulose thru treatment with hydrochloric acid. It was then dried, pulverized, and mixed with S disd in carbon disulfide. After evapn of the CS2, the material was treated with a coned soln of K nitrate, granulated and dried Ref Daniel (1902), 583... 

Bis(tributyltin) oxide is known to break down to inorganic tin under UV irradiation in laboratory conditions (509, 510), and the decomposition may be accelerated by absorbing the organotin compound on a cel-lulosic matrix (511). As bis(tributyltin) oxide is known to react rapidly with carbon dioxide (atmospheric, or trapped in various cellulosic materials, such as cotton or wood) (512), to form bis(tributyltin) carbonate, (BusSnO)2CO, the observed UV degradation pattern may be rationalized in terms of more-ready breakdown of the carbonate than of the oxide, due to the presence of the carbonyl chromophore. The half-life of bis(tributyltin) oxide in pond water has recently been given as 16 days (513). Diorganotin compounds have also been shown to decompose to inorganic tin under UV irradiation (514, 515). 

Bis(tri-ra-butyltin) oxide, BusSnOSnBua, is an organotin chemical very effective in, and widely used for, the protection of such cellulosic materials as cotton textiles, wood, and cellulose-based household-... 

This consists of cellulosic material which has been partially oxidized. White gauze is the most common form, although lint is also used. It can be absorbed by the body in 2-7 weeks, depending on the size. Its action is based prineipally on a meehanieal effect and it is used in the dry state. Since it inactivates thrombin, its activity cannot be enhanced by thrombin ineorporation. 

Capryloamphoglycinate, cocoamphodiacetate, disodium cocoamphodiacetate, lauroamphoacetate, sodium capryloamphohydroxypropyl sulfonate, sodium mixed Cg amphocarboxylate, and alkylamphohydroxypropyl sulfonate Polyvinylpyrrolidone, polyvinyl alcohol, starches, cellulosic material, or partially hydrolyzed polyacrylamide, and polypropylene glycol, or a betaine [43]... 

The stripping of cellulosic materials dyed with reactive dyes is carried out by alkaline reduction followed by hypochlorite oxidation, preceded by a boiling treatment with EDTA if metal-containing dyes have been used. For example, a treatment with 5 gA sodium carbonate or sodium hydroxide and 5g/l sodium dithionite at the boil is followed by a treatment in 0.5-1 °Tw hypochlorite, an antichlor and thorough rinsing. 

Most cellulosic materials contain enough trace-metal catalysts to cause spontaneous ignition with 90% peroxide. 

Wooden staging, which had become impregnated over a number of years with sodium nitrite, became accidentally ignited and burned as fiercely as if impregnated with potassium chlorate. Although the effect of impregnating cellulosic material with sodium nitrate is well known, that due to sodium nitrite was unexpected. 

Fibrous organic material (jute storage bags) is oxidised in contact with sodium nitrate above 160°C and will ignite below 220°C [1]. Wood and similar cellulosic materials are rendered highly combustible by nitrate impregnation [2],... 

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