Cellulose polyanionic

Synonyms Carbor ethylcellulose Carbor ethylcellulose, sodium salt Carboxymethyl ether cellulose sodium salt Cannellose sodium Cellulose carboxymethyl ether Cellulose carbor methyl ether sodium salt Cellulose glycolic acid sodium salt Cellulose gum (INCI) Cellulose, polyanionic Cellulose sodium glycolate CMC CMC sodium salt NaCMC SCMC Sodium carboxymethylcellulose Sodium cellulose glycolate Sodium CMC Sodium CMSodium salt of the polycarbot ethyl ether of cellulose Fornujia RnOCHjCOONa... 

Cellulose monoacetate. See Cellulose acetate Cellulose nitrate. See Nitrocellulose Cellulose, polyanionic. See Carboxymethylcellulose sodium Cellulose powder Cellulose, powdered. See Cellulose Cellulose propionate. See Cellulose acetate propionate Cellulose pulp. See Cellulose... 

Cellulose carboxymethyl ether sodium salt Cellulose glycolic acid sodium salt Cellulose gum (INCI) Cellulose, polyanionic Cellulose sodium glycolate... 

Nondispersed Inhibited Systems. In these systems, the nondispersed character of the fluids is reinforced by some inhibition system, or combination of systems, such as (1) calcium ions, lime or gypsum (2) salt-sodium chloride or potassium chloride (3) polymers such as Polysaccharides, polyanionic cellulose, hydrolyzed polyacrylamide. 

A composition containing polyanionic cellulose and a synthetic polymer of sulfonate has been tested for reducing the fluid loss and for the thermal stabilization of a water-based drilling fluid for extended periods at deep well drilling temperatures [812]. 

Examples of retarders are shown in Table 10-11. They are added to prevent cement from setting too rapidly. These additives are also referred to as set retarders. Cements with retarders to prevent rapid setting may be used at the high-temperature and high-pressure environments of deep wells. Common retarders are lignosulfonate and certain carbohydrate derivatives, such as welan gum, xanthan gum, cellulose, and polyanionic cellulose. 

J. Hen. Sulfonate-containing polymer/polyanionic cellulose combination for high temperature/high pressure filtration control in water base drilling fluids. Patent US 5(X)8025,1991. 

CMC hydrates rapidly and forms dear solutions. Viscosity building is the single most important property of CMC. Dilute solutions of CMC exhibit stable viscosity because each polymer chain is hydrated, extended, and independent. The sodium carboxylate groups are highly hydrated, and the cellulose molecule itself is hydrated. The cellulose molecule is linear, and conversion of it into a polyanion (polycarboxylate) tends to keep it in an extended form by reason of coulombic repulsion. This same coulombic repulsion between the carboxylate anions prevents aggregation of the polymer chains. Solutions of CMC are either pseudoplastic or thixotropic, depending on the type. 

Additional semipermeable membrane—forming polymers are selected from the group consisting of acetaldehyde dimethyl cellulose acetate, cellulose acetate ethyl carbamate, cellulose dimethylamino acetate, semipermeable polyamides, semipermeable polyurethanes, or semipermeable sulfonated polystyrenes. Semipermeable cross-linked selectively permeable polymers formed by coprecipitation of a polyanion and a polycation also can be used for this purpose.22 23 Other polymer materials such as lightly cross-linked polystyrene derivatives, semipermeable cross-linked poly(sodium styrene sulfonate), and semipermeable poly (vinylbenzyltrimethyl ammonium chloride) may be considered.24,25... 

At pH 14, cellulose ionizes to a polyanion (cellulosate) and the hydro-nium counterion (HsO+). Counterions are also called gegenions. 

Pechanek et al. (1982) determined ionic polysaccharides by fl migration through polyacrylamide and agarose gels and on cellulose acetate membranes the polyanions were detected by staining. At the dimensions found in gel micropores, pairs of surfaces create an adsorption potential ( ) 3.5 times that created at the same distance from a single surface (Void and Void, 1983). 

Food-grade CMC is a cellulose carboxylic acid ether with an optimum DS = 0.4-0.7. The higher the DS within this range, the more hydrophilic is the polyanion. Uniformity of substitution makes CMC more compatible with dissolved salts and less inclined to thixotropy than uneven distribution (Feddersen and Thorp, 1993). This gum does not precipitate from a 50% ethanol solution. Below approximately pH 4 in water, the polyanions revert to the un-ionized, water-insoluble acid. CMC viscosity-hysteresis has already been described (Fig. 2 in Chapter 3). CMC dispersions and films have the extra advantage of transparency relative to many other polysaccharide dispersions. The films are resistant to oils, grease, and organic solvents (Hercules, Inc., 1980). 

LCPPac. fioChem] Polyanionic cellulose for oil well drilling plics. 

Plank and Gossen (144) have reported on the temperature dependence of API static filtrate volumes of simple drilling fluids using various polymeric additives. Figure 50 shows the dependence of filtrate volume on temperatures for a base bentonite fluid and with added starch, polyanionic cellulose, and a synthetic sulphonated polymer (39). Starch is an effective fluid loss additive up to about 100 °C whereas the polyanionic cellulose begins to lose its effectiveness at about 140 °C these... 

Some polysaccharides, like pullulan, can be precipitated selectively in plates with ethanol (8). Polyanionic polysaccharides like pectin or carboxy methyl cellulose (CMC) can be precipitated with cetylammonium salts (9, 10). Degradation zones in these plates will not turn opaque upon addition of the precipitant thus revealing the activity of polysaccharases. 

---