Solution thermodynamics of the dextran/methoxy ethylene glycol system

The main thermodynamic parameters were evaluated for the dextran/ methoxy e thylene glycol (MEG) system by viscosity measurements at 25, 30, 35, 40, an d 45 degreesC. The long-range and short-range interaction parameters were d etermined by extrapolation methods, i.e. Kurata-Stockmayer-Fixman, Berry, a nd Inagaki-Suzuki-Kurata equations. Calculated values, as well as the unper turbed root-mean-square end-to-end distance and hydrodynamic expansion fact or, were interpreted mainly on the basis of hydrogen-bond formation between polymer segments and dextran/MEG molecules in solution. The thermodynamic interaction parameter was also evaluated for the same system. The theta tem peratures were obtained from the temperature dependence of the interaction parameter, dependence of (1/2-chi) and the second virial coefficient in the temperature interval of 25 and 45 degreesC for the system and quite a good accordance was indicated with the calculated values evaluated via extrapol ation and interpolation methods. (C) 2001 John Wiley & Sons, Inc.