Carboxy methyl starch

Surface sizes are usually solutions of water-soluble polymers. The most important of which, because of its commercial cheapness, is starch. Other more costly but more specialised film-forming polymers such as soluble cellulose derivatives (particularly carboxy-methyl cellulose), polyvinyl alcohol and alginates are also used. 

In unmodified cellulose the hydroxyl groups give a large amount of hydrogen bonding which leads to insolubility in most solvents. On the other hand if these arc changed by chemical reactions to ether or ester groups a much more tractable material results. Cellulose acetate, butyrate and nitrate methyl and ethyl ether and carboxy methyl ether are widely used modified celluloses. Starches also are modified, but much less commercial success has been had with them. 

Superabsorbent polymers are now commonly made from the polymerization of acrylic acid blended with sodium hydroxide in the presence of an initiator to form a polyacrylic acid, sodium salt (sometimes referred to as cross-linked sodium polyacrylate). Some of the polymers include polyacrylamide copolymer, ethylene maleic anhydride copolymer, cross-linked carboxy-methyl-cellulose, polyvinyl alcohol copolymers, cross-linked polyethylene oxide, and starch grafted copolymer of polyacrylonitrile to name a few. The latter is one of the oldest SAP forms created. 

Physicochemical studies have also been performed on carboxymethyl-ated 0-methyl- and 0-(2-hydroxyethyl)-cellulose. As with other car-boxymethylated polysaccharides, the degree of substitution and the distribution of substituents play a dominant role in the viscosity of aqueous solutions of O-(carboxymethyl)starch. Viscosimetric "" and other measurements indicate that 0-(carboxymethyl)amylose exists as a random coil in solution, " and that the chains are stiffer than the corresponding cel-lulosic chains whereas the stiffness of the chains of 0-(carboxy-methyl)dextran is little different from that of other charged ether derivatives of dextran and dextran sulfate. Fractional precipitation is a useful procedure for obtaining homogeneous fractions of carboxymethylated polysaccharides, as with other polysaccharide ethers. Acetylated O-(carboxymethyl) cellulose provides a useful basis for the formation of desalination membranes. ... 

In the FTIR spectra of CMS 4, it is obvious that apart from the peaks present in starch, there are two additional strong peaks at 1660 cm and 1417 cm that are attributed to the COO groups, which is a clear indication that carboxy-methylation does take place. 

B.S. Kim and S.T. Lim, "Removal of heavy metal ions from water by cross-linked carboxy-methyl com starch", Carbohydr. Polym., Vol. 39, pp. 217-223,1999. 

Comparing with glycerol-plasticized thermoplastic pea starch (TPS)/carboxy-methyl cellulose (CMC) and TPS/microcrystaUine cellulose (MC) composites [226], scanning electron microscope (SEM) showed that there was good adhesion... 

X. Ma, P.R. Chang, and J. Yu, Properties of biodegradable thermoplastic pea starch/carboxy-methyl cellulose and pea starch/microcrystalline cellulose composites. Carbohydr. Polym. 72, 369-375, (2008). 

In order to improve the physical properties of paper, especially strength and resistance to erasure, natural polymers, like starches and gums, are added to the stock, as well as cellulose compounds, like carboxy-methyl cellulose, or synthetic polymers, e.g. polyacrylamides and polyamines. Wet-strength resins, such as polyamide resins, are also often added to the stock. Urea-formaldehyde and melamine-formaldehyde resins are no longer in wider use for improving wet strength. 

In drilling fluid applications, several types of viscosity modifiers can be used to enhance foam stablity. These include partially hydrolyzed polyacrylamide (PHPA) clays, such as bentonite xanthan gum guar gums starches cellulosic polymers, such as hydroxy ethyl cellulose (HEG) and sodium carboxy methyl cellulose (SCMC). In Table 8, base fluid viscosities and drainage times for one-half and four-fifths of the base fluids are recorded in a foam system consisting of an anionic foamer, sodium lauryl sulfate (SLS) and a nonionic foamer, TXlOO - ethoxylated octyl phenol. It can be seen that in these systems base fluid viscosity alone... 

Other depressants that have been nsed are zinc snlfate for sphalerite and cyanide for sphalerite and pyrite, although CMCs (carboxy methyl cellulose - dextrose or starch derivatives) tend to be more commonly used at the present time. 

Numerous ethers of cellulose, starch, and bacterial dextran are of established or potential industrial importance. (See also Chapter XII.) Treatment of the polysaccharides with alkali and methyl chloride, ethyl chloride, benzyl chloride, ethylene oxide (or ethylene chlorohydrin), sodium chloro-acetate, and allyl bromide gives, respectively, the methyl, ethyl, benzyl, hydroxy ethyl, carboxy methyl, and allyl ethers. The cellulose derivatives... 

Nonionic polymers, which can be used as stabilizers are, e.g., starches, polyvinyl alcohols, and polyacrylamides. Nonionic polymers work as protective colloids their mechanism of stabilization is Steric stabilization. Carboxy methyl cellulose bears a small anionic charge along the chain. However, it is often considered to act as a protective colloid. Actually, carboxy methyl cellulose can be considered to use both its protective colloid properties and its charge in stabilizing, thus acting as an electrosteric stabihzer. 

Condensation reactions between hydroxyethyl cellulose or carboxy methyl hydroxy-ethyl cellulose provides potentially useful textile sizing resins.Starch materials have been treated with MA to obtain starch with maleate half-ester residues, with a substitution degree of 0.01-3.00. Styrene monomer is grafted onto the maleate/fumarate residues, with high efficiency, using standard free-radical initiators. 

Dextrin, starch, acrylic, carboxy-methyl cellulose Wallcovering... 

Carboxy methyl cellulose (CMC) A synthetic gum manufactured by reacting monochloroacetate with alkali cellulose. It dissolves both in cold and hot water. It is used in bakery goods (0.05%-0.5%) to improve texture, retain moisture, improve freeze-thaw stability, and lower starch retrogradation. 

Carboxymethylierte Ethoxylate Carboxy-methylated Fatty Alcohol Ethoxylates Carboxymethylstarke Carboxymethyl Starch... 

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