Polysaccharides thixotropy

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). 

Thixotropy Property An aqueous solution of DEAE-dextran graft copolymer is with a thixotropy property as a non-Newtonian fluids, whose transfection solution is suflScient to flow and wet cells through a sheer stress for the solution in the transfection, such as swirling the pan distribute. A water-soluble polysaccharides and copolymers of vinyl coimection are interested for the wet-ability of the cells by the rheological properties[69]. Most reports in the rheological field were on the water-soluble polysaccharides and a few report deals with Graft polymerization of aerylamide (AM) on water-insoluble polysaeeharides such as cellulose [70]. 

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