Collect. Czech. Chem. Commun. 1999, 64, 13-30
https://doi.org/10.1135/cccc19990013

Phase Stability of Hydrogen-Bonded Polymer Mixtures. II. Mixtures of Intercomplexing Polymers

Julius Pouchlý, Antonín Živný* and Antonín Sikora

Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 162 06 Prague 6, Czech Republic

This article is part of serial Phase Stability of Hydrogen-Bonded Polymer Mixtures.

Abstract

Equations for the second derivative of the Gibbs energy of mixing with respect to composition were derived on the basis of the Barker-Guggenheim theory of quasichemical equilibrium for mixtures of two polymers containing polar groups and a nonpolar rest. Using equations derived, conditions for the phase separation in mixtures of two strongly intercomplexing polymer components were evaluated. The phase instability appears when the components differ in their polar group contents (strictly speaking, in their surface fractions in respective macromolecules), or due to an unfavorable interaction between nonpolar groups of the components. The effect is conditioned by small affinity of polar to nonpolar groups and may be influenced by the difference in this affinity between both components; nevertheless, the latter factors are not sufficient for a phase instability to occur.

Keywords: Phase stability; Polymer mixtures; Hydrogen bonds; Intercomplexing polymers; Quasichemical equilibrium theory.