Cellulose carboxymethyl

Carboxymethyl cellulose is obtained by treating alkaline cellulose with chloroacetic acid. 

The properties of the product depend on the degree of substitution (DS 0.3-0.9) and of polymerization (DP 500-2000). Low substitution types (DS 0.3) are insoluble in water but soluble in alkali, whereas higher DS types ( 0.4) are water soluble. Solubility and viscosity are dependent on pH. 

It is a white, odorless powder, having a molecular weight of 90,000-700,000, and is easily dispersed in water to form a clear or colloidal solution. 

2 Safety and Regulatory Status Carboxymethyl cellulose is GRAS listed. 

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The AC may react with methyl chloride or alpha-chloroacetic acid via a direct displacement reaction (eq. 2). The derivatives would be methyl cellulose or carboxymethyl cellulose. 

Lead azide is not readily dead-pressed, ie, pressed to a point where it can no longer be initiated. However, this condition is somewhat dependent on the output of the mixture used to ignite the lead azide and the degree of confinement of the system. Because lead azide is a nonconductor, it may be mixed with flaked graphite to form a conductive mix for use in low energy electric detonators. A number of different types of lead azide have been prepared to improve its handling characteristics and performance and to decrease sensitivity. In addition to the dextrinated lead azide commonly used in the United States, service lead azide, which contains a minimum of 97% lead azide and no protective colloid, is used in the United Kingdom. Other varieties include colloidal lead azide (3—4 pm), poly(vinyl alcohol)-coated lead azide, and British RE) 1333 and RE) 1343 lead azide which is precipitated in the presence of carboxymethyl cellulose (88—92). 

Avicel rnicrocrystaUine cellulose carboxymethyl cellulose FMC Corp. 

Sodium carboxymethyl cellulose [9004-32-4] (CMC) and hydroxyethyl cellulose [9004-62-0] (HEC) are the ceUulosics most widely used in drilling fluids (43). CMC is manufactured by carboxymethylation of cellulose which changes the water-insoluble cellulose into the water-soluble CMC (44). Hydroxyethyl cellulose and carboxymethyl hydroxyethyl cellulose (CMHEC) are made by a similar process. The viscosity grade of the material is determined by the degree of substitution and the molecular weight of the finished product. 

Milk. Imitation milks fall into three broad categories filled products based on skim milk, buttermilk, whey, or combinations of these synthetic milks based on soybean products and toned milk based on the combination of soy or groundnut (peanut) protein with animal milk. Few caseinate-based products have been marketed (1,22,23). Milk is the one area where nutrition is of primary concern, especially in the diets of the young. Substitute milks are being made for human and animal markets. In the latter area, the emphasis is for products to serve as milk replacers for calves. The composition of milk and filled-milk products based on skim milk can be found in Table 10. Table 15 gives the composition of a whey /huttermilk-solids-hased calf-milk replacer, which contains carboxymethyl cellulose (CMC) for proper viscosity of the product. 

Follicle Stimulating Hormone (FSH, foilitropin) [9002-68-0] Mr 36,000. Purified by Sephadex GlOO gel filtration followed by carboxymethyl-cellulose with NH4OAC pH 5.5. The latter separates luteinising hormone from FSH. Solubility in H2O is 0.5%. It has an isoelectric point of 4.5. A soln of Img in saline (lOOmL) can be kept at 60° for 0.5h. Activity is retained in a soln at pH 7-8 for 0.5h at 75°. The activity of a 50% aq EtOH soln is destroyed at 60° in 15 min. [Bloomfield et al. Biochim Biophys Acta 533 371 1978 Hartree Biochem J100 754 1966 Pierce and Parsons Ann Rev Biochem 50 465 1981.]... 

Extract separated by ion-exchange on carboxymethyl cellulose, desalted, evapd and lyophilised, then chromatographed on Sephadex G-25. [Lande etal. Biochem Prep 13 45 1971.]... 

Pituitary Growth Factor (from human pituitary giand) [336096-71-0]. Purified by heparin and copper affinity chromatography, followed by chromatography on carboxymethyl cellulose (Whatman 52). [Rowe et al. Biochemistry 25 6421 1986.]... 

Anionic, hydrophilic Sodium polyacrylate, sodium hyaluronate, carboxymethyl cellulose 0.1-0.3 M salt/buffer, pH 7-9... 

Table 2. Swelling of polyacrylamide hydrogels crosslinked with allyl ether of carboxymethyl cellulose (AE CMC)1 [41]...

Mucoadhesion Involving Guar, Alginate, Carboxymethyl Cellulose,... 

The main polymers used as thickeners are modified celluloses and poly(acrylic acid). Several different modified celluloses are available, including methyl-, hydroxypropyl methyl-, and sodium carboxymethyl-cellulose and their properties vary according to the number and distribution of the substituents and according to relative molar mass of the parent cellulose. Hence a range of materials is available, some of which dissolve more readily than others, and which provide a wide spread of possible solution viscosities. Poly(acrylic acid) is also used as a thickener, and is also available in a range of relative molar masses which give rise to give solutions of different viscosities. 

Some part of the cellulose fraction is redirected to make cellulose derivatives, such as cellulose acetate, methyl and ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose. These derivatives find multiple applications, for instance, as additives in current products (e.g., paints, lacquers) of chemical industry. Typically, the preparation of cellulose derivatives takes place as a two-phase reaction cellulose is pretreated, for example, with alkali, and a reagent is added to get the substitution. Usually no catalyst is needed [5]. 

Macrochromatographlc Methods. These procedures use cation exchangers, such asAmberllte-IRC-50, carboxymethyl-Cellulose (CMC) and carboxymethyl-Sephadex (CMS), and the anion exchangers diethylamlnoethyl-(DEAE)-Cellulose and DEAE-Sephadex. 

Synthetic examples include the poly(meth)acrylates used as flocculating agents for water purification. Biological examples are the proteins, nucleic acids, and pectins. Chemically modified biopolymers of this class are carboxymethyl cellulose and the lignin sulfonates. Polyelectrolytes with cationic and anionic substituents in the same macromolecule are called polyampholytes. 

Biodegradable drilling fluid formulations have been suggested. These are formulations of a polysaccharide in a concentration insufficient to permit a contaminating bacterial proliferation, namely a high-viscosity carboxymethyl-cellulose sensitive to bacterial enzymes produced by the degradation of the polysaccharide [1419]. 

A mixture of polymers that can serve as a plugging solution when taken in an equimolar ratio consists of polydimethyl-di lyl ammonium chloride, which is a strongly basic cation-active polymer, and the sodium salt of carboxymethyl-cellulose, which is an anion-active polymer. The aqueous solution contains 0.5% to 4% of each polymer. Gelling occurs because the macro ions link together from different molecules. The proposed plugging composition has high efficiency within a wide pH range [497]. 

Y. T. Kalashnikov. Lubricant-sealer for profiled joints of casing pipes— contains soap plastic lubricant, polyacrylamide or carboxymethyl cellulose and additionally gypsum or cement powder, to increase sealing rate. Patent RU 2007438-C, 1994. 

V. S. Kotelnikov, S. N. Demochko, V. G. Fil, and I. S. Marchuk. Drilling mud composition—contains carboxymethyl cellulose, acrylic polymer, ferrochrome lignosulphonate, cement and water. Patent SU 1829381-A, 1996. 

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