Hydrodynamic behavior, cellulose

Linear polymers, polystyrene and cellulose triacetate exhibit differences in hydrodynamic behavior in solution. Cellulose and its derivatives are known to have highly extended and stiff chain molecules below a Dp of about 300, but as the Dp Increases above 300 the chain tends to assume the character of a random coll (27,28). The assumption that hydrodynamic volume control fractionation in GPC may not be true for polystyrene and cellulose triacetate, though it has been found satisfactory for non-polar polymers in good solvents (29). 

Holtzer, A. M., H. Benoit and P. Doty The molecular configuration and hydrodynamic behavior of cellulose trinitrate. J. Phys. Chem. 58, 624 (1954). 

Earlier reviews have summarized some results of physical studies on polysaccharide solutions, but have made no attempt to deal in detail with the problems involved. The primary aim here is to cover (1) problems arising in the application of physical techniques to polysaccharide solutions, and (2) the interpretation of the data in terms of current theories of the hydrodynamic behavior of polymer solutions. No attempt will be made to deal with the entire field, but, instead, particular polysaccharides will be chosen which have been studied in sufficient detail to illustrate the polymer theories. Further, in view of the large amount of specialized work carried out on cellulose and its derivatives, this field is considered to be a separate entity and will not be treated. ... 

Dextran samples of a narrow molecular weight distribution have been used as calibration standards (100). However, dextran is a polymer composed of 1,6-linked glucose units. The glucopyranose rings in this polymer are connected through three bonds, as opposed to the two bonds found in cellulose. Thus, dextran is more flexible than cellulose and, as such, may not accurately represent the hydrodynamic behavior of cellulose. 

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