X cellulosics

Fig. 127. Nitrogen content in nitrocellulose as a function of HNO3 concentration in carbon tetrachloride. Ratio of reactants 5 l x (cellulose CCUiHNOj) (Kenyon et al. [47]).

Fig. 129. Influence of the content of HNO3 in nitric acid-N204 solution in CCI4 on nitrogen content of nitrocellulose. Ratio of reactants 5 60 60 x (cellulose N204 CCl4 HN03) (Kenyon ef al. [47]).

Fig. 3 Effect of xylanase addition on digestibility of Avicel (C + P-G cellulose + p-glucosidase, C + P-G + X cellulose + P-glucosidase + xylanase)...

The principal commercial sources of chemical cellulose are purified cotton linters of about 99 per cent a-cellulose content and purified wood pulp of about 96 per cent cellulose content. Cellulose occurs in these materials as a fairly highly crystalline, high-molecular-weight polymer. It is in a fibrous form, which is insoluble in common reagents. Cellulose wUl not react to any significant d ee with acetic acid and will react with acetic anhydride without a catalyst only at very high temperatures, at which the cellulose is degraded. 

Nitto Electric NRO-A (first stage) Tubular, 190 mmcf) x Cellulose 50 kg/cm ... 

Shin J.-H., Kondo X, Cellulosic blends with poly(acrylonitiile) Characterization of hydrogen bonds using regioselectively methylated cellulose derivatives. Polymer, 39, 1998, 6899-6904. 

Typical wood samples contain approximately 40 X> cellulose, and cotton is nearly 90%. Cellulose has a pseudocrystalline structure in the form of fibrils that are bonded together by the lignin and hemicellulose. Flemicellulose is also a saccharide-based biopolymer composed of subunits of glucose, galactose, mannose, and xylose, to name a few. The most coirunon subunit is the xylans, as shown in Figure 13.17. Hemicelluloses constitute approximately 25% of wood... 

Fig. 10.28. Decrease of intrinsic viscosity of ( ) polystyrene (O) poly(methyl methacrylate) and (x) cellulose during UV irradiation (253.7nm) at 25°C [980]. (Reproduced with permission from [980] published by John Wiley Sons, Inc., 1979.)...

Sunohara, X, Masuda, X Cellulose triacetate as a high-performance membrane. Contrib. Nephrol. 173,156-163 (2011)... 

Glycerol ct-dichlorohydrin, sym-dichloroiso-propyl alcohol, 1,3-dichloro-2-hydroxypropane, CH2CI-CHOH-CH2C1. Colourless liquid with an ethereal odour b.p. 174-175" C. Prepared by passing dry HCl into glycerin containing 2% elhanoic acid at 100-1 lO C. Converted to x-epichlorohydrin by K.OH, Used as a solvent for cellulose nitrate and resins. 

Cellulose is the main component of the wood cell wall, typically 40—50% by weight of the dry wood. Pure cellulose is a polymer of glucose residues joined by 1,4-P-glucosidic bonds. The degree of polymerization (DP) is variable and may range from 700 to 10,000 DP or more. Wood cellulose is more resistant to dilute acid hydrolysis than hemiceUulose. X-ray diffraction indicates a partial crystalline stmcture for wood cellulose. The crystalline regions are more difficult to hydrolyze than the amorphous regions because removal of the easily hydrolyzed material has Htde effect on the diffraction pattern. 

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. 

Unit cells of pure cellulose fall into five different classes, I—IV and x. This organization, with recent subclasses, is used here, but Cellulose x is not discussed because there has been no recent work on it. Crystalline complexes with alkaU (50), water (51), or amines (ethylenediamine, diaminopropane, and hydrazine) (52), and crystalline cellulose derivatives also exist. Those stmctures provide models for the interactions of various agents with cellulose, as well as additional information on the cellulose backbone itself. Usually, as shown in Eigure la, there are two residues in the repeated distance. However, in one of the alkah complexes (53), the backbone takes a three-fold hehcal shape. Nitrocellulose [9004-70-0] heUces have 2.5 residues per turn, with the repeat observed after two turns (54). 

During World War I, cellulose acetate replaced the highly flammable cellulose nitrate coating on airplane wings and the fuselage fabrics. After World War I, it found extensive use in photographic and x-ray films, spun fibers, and mol ding plastics. 

FIG. 22-77 Influence of feed purity on total membrane area when the residue gas at fixed purity is the product, Feed-gas volume is constant, CO2/CH4 cellulose-acetate membrane, (X = 21, Courtesy VP R. Grace.)... 

Standardized techniques atomic absorption (AAA) and photometric (FMA) of the analysis and designed by us a technique X-Ray fluorescence of the analysis (XRF) for metals definition in air of cities and the working areas of plants to production of non-ferrous metals are applied. The samples of aerosols were collected on cellulose (AFA-HA) and perchlorovinyl (AFA-VP and FPP) filters (Russia). The techniques AAA and FMA include a stage of an acid-temperature ashing of a loaded filter or selective extraction of defined elements from filter by approaching dissolvent. At XRF loaded filters were specimens. 

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