Cellulose INDEX

Interpret the slope and intercept values of the line in Fig. 10.12 in terms of the molecular weight and radius of gyration of cellulose nitrate in this solution. At 436 nm the refractive index of acetone is 1.359. 

The bulk density of cellulose acetate varies with physical form from 160 kg/m (10 lb /ft ) for soft dakes to 481 kg/m (30 lb /fT) for hammer-milled powder, whereas the specific gravity (1.29—1.30), refractive index (1.48), and dielectric constant of most commercial cellulose acetates are similar. 

If paraffin permeates a white opaque paper, one can read letters through the paper because the paper becomes transparent. This phenomenon is based on the simple principle that micropores in the paper are filled with paraffin, which has a refractive index that is close to that of cellulose. If the porous PVA-PVAc composite film is soaked in organic solvents having the same refractive indices as that of PVA, the porous film is expected to become transparent again, according to the same principle as the phenomenon between paraffin and cellulose. On the basis of this consideration, subsequent experi-... 

Bleached cotton stalk pulp is treated with different concentrations of ethylene diamine (50-100%) for 20 min. It is clear that the crystallinity index (CrI) of these treated pulps is decreased by increasing the concentration of ethylene diamine that is, the decrystallization increases. The degree of polymerization is nearly the same, but some increase is shown in the sample treated with 100% ethylene diamine. This indicates that 100% ethylene diamine may act as a dissolving agent for low degree of polymerization (DP) of cellulosic chains and hemicellulose. 

The second choice is a simpler solution. According to Sarko and Muggli,66 all 39 observed reflections in the Valonia X-ray pattern are indexable by a two-chain triclinic unit cell with a = 9.41, b =8.15 and c = 10.34 A, a = 90°, 3 = 57.5°, and y = 96.2°. Ramie cellulose, on the other hand, is completely consistent with the two-chain monoclinic unit cell. Also, there are significant differences between their high-resolution solid-state l3C NMR spectra, indicating that Valonia and ramie celluloses, the two most crystalline forms, reflect two distinct families of biosynthesis. On this basis, the Valonia triclinic and the ramie monoclinic forms are classified69 as Ia and Ip, respectively. It has been shown from a systematic analysis of the NMR spectra by these authors, and from electron-dif-... 

Fig. 4a. Resolution of racemic (67) by column chromatography on microcrystalline cellulose triacetate (column B) and by recrystallization 35) C = crystals M = mother liquor the index following C or M gives the number of recrystallizations the fraction has undergone. The value of [ot] ° is given, followed by the quantity obtained...

The unit cell of cellulose from Chaetomorpha melagonium is monoclinic, with a = 16.43 A (1.643 nm), b(fiber axis) = 10.33 A (1.033 nm), c = 15.70 A (1.570 nm), and /3 = 96.97°. In base-plane projection, each of the Meyer-Misch subcells that make up the super-lattice are identical. All equatorial reflections can be indexed by using a one-chain unit-cell, meaning that every single chain has... 

Drying equipment, 10 154 Drying gases, commercial gas absorption process for cellulose acetate fiber production, l 26t Drying index, 9 144 Drying mechanisms, 9 102-116. 

The vat dyes section of the Colour Index incorporates a subgroup called solubilised vat dyes. These are sodium salts of sulphuric acid esters of the parent leuco vat dyes, such as Cl Solubilised Vat Blue 6 (1.50). In contrast to the leuco compounds, the vat leuco esters dissolve readily in water at neutral pH. They have relatively low substantivity for cellulose and thus have been used mainly in continuous dyeing and printing. In the presence of an oxidant in mineral acid solution (sodium nitrite and sulphuric acid, for example) the leuco ester is rapidly decomposed and the insoluble vat dye regenerated. Thus application of a vat leuco ester represents a simpler (but more costly and less versatile) alternative to conventional dyeing methods via the alkaline leuco compound. 

These are the only ranges of precursor products in the Colour Index that are still commercially significant. Azoic dyes have a close formal relationship to those monoazo pigments derived from BON acid or from acetoacetanilides (section 2.3.1) and some are chemically identical with them, although they are used in a totally different way. Azoic components are applied to produce insoluble azo dyes within the textile substrate, which is almost always cotton. Corresponding azoic components for the dyeing of cellulose acetate, triacetate and polyester fibres were once commercially important, but are now obsolete because of environmental hazards and the time-consuming application procedure. 

Iogen (2005). Cellulose Ethanol Demonstration Facility, www.iogen.ca/company/ facilities/index.html. 

Choice of Solvent. JJ-Methylpyrrolidone (NMP) was initially used as the mobile phase but proved to be unsatisfactory because of (i) high solution viscosities, (il) exceedingly small differences in refractive index between NMP and cellulose triacetate solutions, (ill) erratic base line. In view of this dichloromethane was employed. Some additional benefits derived from this mobile phase are (i) a decrease in elution volume due to low solution viscosities, (il) fast solvent recovery due to low boiling point of dichloromethane and (iii) ease of obtaining preparative GPC cuts of cellulose triacetate. 

The principal filler used for the production of light-colored urea plastics is alpha cellulose, which has an index of refraction similar to that of the urea ... 

Evaluate M, B, and Rg for cellulose nitrate in acetone at 25°C from these data. Use 1.359 for the refractive index of acetone at this wavelength. 

Especial points which emerge from these studies include (a) the almost complete absence of reactivity of the hydroxy-groups of simple carbohydrates in water, which is attributed to their powerful solvation by water preventing a close approach of any other solute and (b) the ability of ester groups to interact with proton-acceptors. The refractive index tests, examination of m.p. or b.p., and infrared spectra of certain mono- and poly-esters appear to be interpreted most simply by assuming the formation of weak CH bonds by ester groups under the activating influence of the adjacent (5—0 double bond. These bonds can account for certain properties of l 2-diesters and for the adsorption of proton-acceptor solutes by cellulose acetates. 

New International Dictionary, Merriam Co, Springfield, Mass(195I), 73 Alperox C. Trade name for tech lauroyl peroxide manufd by the Lucidol Division of Wallace Tieraan, Inc, Buffalo, NY Alpha-Cellulose is that portion of cellulosic materialfpulp, paper, etc) which,after treatment with 17,5% NaOH(mercerized strength) at 20° and diln to 7.3% NaOH,can be separated by filtration. The residue of alpha-cellulose is a good index of the undegraded cellulose content of the material. The alkali treatment removes degraded(oxidized or hydrolyzed) cellulose and short chain material. Some pentosans and hexosans may... 

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