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Statistical thermodynamics predictions of the solubility parameter
Author(s) -
Utracki LA,
Simha R
Publication year - 2004
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.1365
Subject(s) - thermodynamics , van der waals force , solubility , polymer , scaling , equation of state , heat capacity , hildebrand solubility parameter , chemistry , molar volume , lattice (music) , molar mass , statistical physics , materials science , physics , molecule , organic chemistry , mathematics , geometry , acoustics
The Simha and Somcynsky (S‐S) lattice‐hole theory has been shown to represent accurately the pressure–volume–temperature ( PVT ) surface of chain molecular melts and their mixtures. The characteristic scaling parameters, P *, T * and V *, extracted from equation of state (eos) measurements, are known for a large number of polymers. On this basis it is possible to compute the configurational internal energy density and thus the solubility parameter δ as a function of temperature and pressure, δ = δ( T , P ). In the first part of this paper it is shown that the theory leads to an energy approximately proportional to the first power of density, that is of the van der Waals type, as found for low molar mass fluids by Hildebrand. We continue with a computation of δ for a series of polymer melts at two levels of temperature, namely T = 25 °C and T = T g + 300 K. Next, the results are compared with those listed in reference publications, all at ambient pressure. The theoretical values extrapolated from the melt to 25 °C were systematically higher than those listed. However, good correlation is obtained with the high‐temperature calculations for a large variety of polymers. Arguments for this low–high temperature correlation are presented in terms of corresponding levels of molecular mobility and packing in solution and in bulk. Copyright © 2004 Society of Chemical Industry