Absolute prediction of upper and lower critical solution temperatures in polymer solutions from corresponding states theory: a semi-empirical approach

Abstract

Application of the corresponding states theory to phase equilibria in polymer solutions as formulated by both Flory and Patterson has been shown to provide only a qualitative description of the systems studied. A more quantitative agreement between theory and experiment can be obtained if the solvent temperature reduction parameter T^☆₁ is selected using a semi-empirical method which is embodied in the equation T^☆₁/K =–17 491 + 74.774 T_c–61.085 × 10^–3T²_c where T_c is the solvent critical temperature. This modified approach leads to an absolute prediction of lower critical solution temperatures from measurements of only upper critical solution temperatures, and vice versa, although the latter is less accurate. The limitations of the method are discussed and alternative procedures for data analysis are examined, none of which appears to be an improvement.