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Solubility profiles of poly(ethylene glycol)/solvent systems. II. comparison of thermodynamic parameters from viscosity measurements
Author(s) -
Di̇nç Cemile Özdemir,
Ki̇barer Günay,
Güner Ali
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.31829
Subject(s) - thermodynamics , virial coefficient , solubility , hildebrand solubility parameter , aqueous solution , solvent , flory–huggins solution theory , enthalpy , viscometer , dilution , ethylene glycol , intrinsic viscosity , chemistry , tetrahydrofuran , atmospheric temperature range , theta solvent , extrapolation , viscosity , polymer , solvent effects , organic chemistry , physics , mathematical analysis , mathematics
Solution thermodynamics of PEG samples in aqueous and nonaqueous (methanol, chloroform, tetrahydrofuran, and dimethylsulfoxide) solutions have been investigated by viscometric studies at 25, 30, 35, and 40°C. The hydrodynamic expansion factor, a h , and the unperturbed root mean square end‐to‐end distance, $ \langle r^{2}\rangle_\theta^{1/2} $ , found for the system indicated that the polymer coils contract as the temperature is raised. The long‐range interaction parameter, B , was also evaluated and a significant decrease with increasing temperature was observed. The theta temperatures, θ, obtained from the temperature dependence of (1/2 − χ) and the second virial coefficient, A 2 , are quite good in agreement with the calculated values evaluated via extrapolation and interpolation methods. The thermodynamic interaction parameter, χ, was evaluated through the sum of the individual values of enthalpy and entropy dilution parameters for PEG samples. The restrictions applying to the establishment of concentration regimes, short‐range, and long‐range interactions are discussed. A parallelism is found between solubility profiles obtained by solution viscometry and solubility parameter approaches for PEG/solvent systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010