Cellulose methods

CoAd Blood Testing oa Sickle Cell Anemia and Related Vl6-oAdeAS by AlienachAomatogAaphlc Methods. The CM-Sephadex procedure easily detects Hb-S and Hb-C at birth but the diffuse zone of Hb-A has on occasion been difficult to see. Substitution of CM-Cellulose for CM-Sephadex has yielded a superior mlcrochromatographlc method, and the compact, well-defined zones of the CM-Cellulose column facilitate the Interpretation of the results even though the amount of sample Is only 20% as great. The CM-Cellulose method Is as simple and rapid as the original CM-Sephadex procedure (27. 28). 

Detection of irradiated food containing cellulose - Method by ESR-spectroscopy... 

Cellulose (method 15, above). In first quality flour, the cellulose does not exceed 0 3% (0 34% on the dry matter). It increases in the lower qualities up to 1% (1 15% on the dry matter) for flour with a high ash. Wood-meal, ivory-nut meal and the like should not be present. 

Cellulose Method Percent Graft M.Wt.xlO-5 of Grafted Side Chains Cellulose Chains per Grafted Side Chain... 

Barth, H. G., and Regnier, F. E. (1981). High-performance gel-permeation chromatography of industrial gums analysis of pectins and water-soluble cellulosics. Methods in Carbohydrate Chemistry, Vol. IX, pp. 105-114. Academic Press, New York. 

Carbon and oxygen isotope analysis of lake sediment cellulose methods and applications. Brent B. Wolfe, Thomas W. D. Edwards, Richard J. Elgood Kristina R. M. Beming.373... 

The ANP has a spherical to elliptical shape with diameter from 80 to 120 nm depending on the origin of cellulose, method, and conditions of isolation (Figure 9.12). It was discovered that after prolonged sonication the particle diameter can be reduced to 50—80 nm (Zhang et al., 2007). 

The derivatives are hydroxyethyl and hydroxypropyl cellulose. AH four derivatives find numerous appHcations and there are other reactants that can be added to ceUulose, including the mixed addition of reactants lea ding to adducts of commercial significance. In the commercial production of mixed ethers there are economic factors to consider that include the efficiency of adduct additions (ca 40%), waste product disposal, and the method of product recovery and drying on a commercial scale. The products produced by equation 2 require heat and produce NaCl, a corrosive by-product, with each mole of adduct added. These products are produced by a paste process and require corrosion-resistant production units. The oxirane additions (eq. 3) are exothermic, and with the explosive nature of the oxiranes, require a dispersion diluent in their synthesis (see Cellulose ethers). 

The two procedures primarily used for continuous nitration are the semicontinuous method developed by Bofors-Nobel Chematur of Sweden and the continuous method of Hercules Powder Co. in the United States. The latter process, which uses a multiple cascade system for nitration and a continuous wringing operation, increases safety, reduces the personnel involved, provides a substantial reduction in pollutants, and increases the uniformity of the product. The cellulose is automatically and continuously fed into the first of a series of pots at a controlled rate. It falls into the slurry of acid and nitrocellulose and is submerged immediately by a turbine-type agitator. The acid is deflvered to the pots from tanks at a rate controlled by appropriate instmmentation based on the desired acid to cellulose ratio. The slurry flows successively by gravity from the first to the last of the nitration vessels through under- and overflow weirs to ensure adequate retention time during nitration. The overflow from the last pot is fully nitrated cellulose. 

There are many chemical methods for generating radicals reported in the hterature that do not involve conventional initiators. Specific examples are included in References 64—79. Most of these radical-generating systems carmot broadly compete with the use of conventional initiators in industrial polymer apphcations owing to cost or efficiency considerations. However, some systems may be weU-suited for initiating specific radical reactions or polymerizations, eg, grafting of monomers to cellulose using ceric ion (80). 

A review covers the preparation and properties of both MABS and MBS polymers (75). Literature is available on the grafting of methacrylates onto a wide variety of other substrates (76,77). Typical examples include the grafting of methyl methacrylate onto mbbers by a variety of methods chemical (78,79), photochemical (80), radiation (80,81), and mastication (82). Methyl methacrylate has been grafted onto such substrates as cellulose (83), poly(vinyl alcohol) (84), polyester fibers (85), polyethylene (86), poly(styrene) (87), poly(vinyl chloride) (88), and other alkyl methacrylates (89). 

The availabihty of spray-dried lactose, microcrystaUine cellulose, and other excipients allows for the use of granular rather than powdered phases. This eliminates some of the problems of particle segregation according to size (demixing) and even flow to the die. Direct compression eventually may be the preferred method of tablet preparation. 

Acids and alkaUes were used to decompose the fiber to cellulose. The alkaU digester process, developed in 1899, is stiU used. Fiber glass reinforcement must be removed mechanically before the mbber can be reclaimed. A highly efficient method involves hammer mills and reel beaters to separate the fiber from the mbber an air current subsequentiy drives off the fiber. 

Blends of polyester with cotton (qv) or viscose are first dyed with disperse dyes, then with sulfur dyes (see Fibers, polyester Fibers, regenerated CELLULOSics). Disperse and sulfur dyes can also be appHed simultaneously in a pad—dry—thermofix/chemical reduction pad—steam sequence. In this case, the sulfur dyes cannot be used in thein reduced form because of the effect of the sodium sulfide on the disperse dye. Therefore, this method is confined to the solubilized sulfur dyes or sulfur dyes in the dispersed form. 

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