Cellulose ethers carboxymethylcellulose

Carboxymethylcellulose, polyethylene glycol Combination of a cellulose ether with clay Amide-modified carboxyl-containing polysaccharide Sodium aluminate and magnesium oxide Thermally stable hydroxyethylcellulose 30% ammonium or sodium thiosulfate and 20% hydroxyethylcellulose (HEC) Acrylic acid copolymer and oxyalkylene with hydrophobic group Copolymers acrylamide-acrylate and vinyl sulfonate-vinylamide Cationic polygalactomannans and anionic xanthan gum Copolymer from vinyl urethanes and acrylic acid or alkyl acrylates 2-Nitroalkyl ether-modified starch Polymer of glucuronic acid... 

Eyler,26 who determined the copper iodometrically after precipitation of copper carboxymethylcellulose phosphates interfered with this analysis. A more satisfactory precipitating agent was found to be uranyl nitrate hexahydrate,26 though earlier investigations21 had shown that carboxymethylcellulose precipitates more than the theoretical amount of uranium. Mention should be made of the original analytical method developed by Kalle and Co.,26a in which the cellulose ether was determined by dichromate oxidation. 

Classical cellulose ethers, such as carboxymethylcellulose (CMC), alkyl-cellulose, and hydroxyalkylcellulose will not be discussed here. Readers should refer to classical publications [6,18,67,88]. 

Major industrial uses for chloroacetic acid are in the manufacture of cellulose ethers (mainly carboxymethylcellulose, CMC), herbicides, and tliioglycolic acid. Other industrial uses include manufacture of glycine, amphoteric surfactants, and cyanoacetic acid. 

Substituted Cellulose Ethers. Since their introduction for ophthalmic use, MC and other substituted cellulose ethers such as hydroxyethylcellulose, hydroxypropylcel-lulose, hydroxypropyl methylcellulose (HPMC), and carboxymethylcellulose (CMC) have been used in artificial tear formulations.These colloids dissolve in water to produce colorless solutions of varying viscosity. They have the proper optical clarity, a refractive index similar to the cornea, and are nearly inert chemically. Their relative lack of toxicity, their viscous properties, and their beneficial effects on tear film stability have made cellulose ethers useful components of artificial tear preparations. Historically, the most frequently used representative of this group was MC. 

Semisynthetic. This group (sometimes called water-soluble resins) includes such chemically treated natural polymers as carboxymethylcellulose, me-thylcellulose, and other cellulose ethers, as well as various kinds of modified starches (ethers and acetates). 

Other non-ionic cellulose ethers which have been stndied in the formulation of hydrophilic matrices include high viscosity grades of hydroxypropylcellulose (HPC) and hydroxyethylcellulose (HEC) [24]. The ionic cellulose ether, sodium carboxymethylcellulose (Na CMC), with low or medium viscosity grades has... 

Cellulose ethers can be prepared by various methods, as by using the common Williamson ether synthesis, with alkyl halides in the presence of a strong base (Fig. 32). This procedure is most often used to introduce carboxyl functions [O-carboxymethylcellulose (CMC)] or hydroxyl groups [3-hydroxypropylcellulose (HPC) and 2-hydroxyethylcellulose (HEC)]. 

Synonyms Calcium cellulose glycolate Carboxymethylcellulose calcium Carmellose calcium Cellulose carboxymethyl ether calcium salt... 

Methods for the SEC analysis of ethyl cellulose (21,57) hydroxyethyl cellulose (57,79) cellulose acetate butyrates (80) allylated methylcellulose, triallyl cellulose, and glycidyl cellulose (48) tetrahydropyranyl cellulose, tetrahydropyranyl hydroxyethyl cellulose, and tetrahydropyranyl methylcellulose (14) carboxymethylcellulose (11,91) and cellulose ethers (97) have been described in... 

Health and Safety Factors. No adverse toxicological or environmental factors are reported for cellulose ethers in general (33,60-73). Some are even approved as direct food additives, including purified carboxymethylcellulose, methyl-cellulose, hydroxypropylmethylcellulose, and hydroxypropylcellulose. 

Properties. Sodium carboxymethylcellulose [9004-32-4] (CMC), also known as cellulose gum, is an anionic, water-soluble cellulose ether available in a wide range of substitution. The most widely used types are in the 0.7-1.2 DS range. Water solubility is achieved as the DS approaches 0.6 as the DS increases, solubility increases. The rate at which CMC dissolves depends primarily on its particle size. Finely ground material dissolves faster than coarser grades. The coarse material. 

Since the CM-cotton developments were designed for healthcare applications, the CM-products were sterilized with ethylene oxide (EO). The products passed the cell culture, primary skin irritation and intracutaneous irritation tests. Safety evaluation on an animal model is yet to be completed. No adverse toxicological or environmental factors are reported for cellulose ethers in general. In fact, some purified carboxymethylcelluloses, methylcelluloses, and hydroxypropylcelluloses are approved as direct food additive [8]. A significant use of CM-cellulose is also found in pharmaceuticals for skin care products such as ointments, lotions, and creams [9]. 

Soluble synthetic polymers—from polymers including polyvinyl alcohol, cellulose ethers, meth-ylcellulose, carboxymethylcellulose, and polyvinylpyrrolidone... 

F. carboxymethylcellulose C. is the most common cellulose ether because it is versatile and can be manufactured easily. For details concerning structure - cellulose ethers. DS values range from 0.3-1.2. 

Carboxymethylcellulose Sodium. Carboxymethyl ether of cellulose sodium salt (Citmcel) (8) is a white granular substance soluble in water depending on the degree of substitution. It is equally soluble in cold and hot water and may be prepared by treating alkaU cellulose with sodium chloroacetate. 

Carboxymethylcelluloses (CMC). CarboxymethylceUulose [9004 2-6] (CMC) is the carboxymethyl ether of cellulose. To prepare CMC, cellulose is steeped in sodium hydroxide solution, and the so-called alkaU cellulose is treated under controlled conditions with sodium monochloroacetate to form the sodium salt of CarboxymethylceUulose and sodium chloride. Therefore, the CMC of commerce is actuaUy sodium CarboxymethylceUulose... 

Cellulose may be converted from a water-insoluble polymer to a water-soluble polymer by the partial etherification of some of the hydroxyl groups by dimethyl sulfate. When the degree of substitution (DS) is 1.5 to 2.0, the hydrogen bonds are sufficiently weakened, and the methylcellulose is soluble in water. Carboxymethyl ethers, such as carboxymethylcellulose (CMC), are also water-soluble. The degree of solubility is related to the DS of the polymer and the pH of the solvent. 

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