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Reduced viscosity (q&) and Inherent viscosity (Inq,I/c) of dilute solution of water soluble polysaccharide polymer "Dextran" has been calculated by measuring the flow time of the polymer solution in solvents like 6(M) Urea, 2(M) Glycine and 50% Glucose at three different temperatures -25"C, 30°C and 35°C. From extrapolation of curve (q,/c) versus (c) and On qrel/c) versus (c), thermo viscosity parameters like Huggins' constant (Vv), Kraemer's constant (PA) and viscosity concentration coefficient (uz) have been estimated which enable us to know the fate of the polymer molecules in these solvents.

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In this paper, the authors have given information regarding intermolecular interactions of aqueous dextran solution in urea. The behavior of dextran in urea has been examined by the help of ultrasonic interferometer working at frequency 5MHz at different temperatures ranging from 303 K to 323 K in 5K interval. Ultrasonic speed, density, viscosity measurements have been used for the evaluation of thermodynamic parameters like Gibb’s free energy (ΔG) as well as acoustical parameters are acoustic impedance (Z), isentropic compressibility (β), intermolecular free length (Lf ) and relaxation time (τ), etc. The results have been used to throw light on the nature of the interaction among solute and solvent, interpreted in the light of structural rearrangement occurs in the aqueous dextran and urea solution.

Some thermo-viscosity parameters like Viscosity-molecular weight constant (K), the short-range parameter, (A) and long-range parameter (B) have been evaluated for the polymer "Dextran" of three different molecular weights (M w ϭ 19,500, 75,000, and 250,000) in three different solvents like 6 (M) aqueous urea, 2 (M) aqueous glycine, and 50% aqueous glucose at temperatures ranging from 25 to 50°C. The study reveals that the viscosity-molecular weight constant (K) decreases with increase in temperature for polar solvents like aqueous urea and aqueous glycine. The value of "K" increases with the rise in temperature within the range of 25 to 35°C in case of a nonpolar solvent aqueous glucose and then "K" decreases with the increase in temperature within the range of 40 to 50°C for the nonpolar solvent aqueous glucose. The short-range parameter (A) shows the same trend as shown by "K" and the longrange parameter "B" exhibits no definite trend with the variation of temperature.