R. Horst and B. A. Wolf

"Phase diagrams calculated for quaternary polymer blends"

*Journal of Chemical Physics* **1995**, *103*, 3782-3787.

**Abstract:** A method is presented that allows the calculation of phase
diagrams (spinodal, binodal, and tie lines) of quaternary mixtures on the basis
of the Gibbs energy of mixing Delta G. No derivatives of Delta G with respect
to the composition variables are required. This method is particularly useful
in cases where the composition dependence of Delta G is very complex, and no
analytical representation of Delta G can be found. Phase diagrams have been
calculated on the basis of the Flory-Huggins theory for mixtures of four polymers.
Blends that phase separate because of very favorable interactions (negative
interaction parameters) were of particular interest. In this case miscibility
gaps can be located inside the tetrahedron composed of the Gibbs phase triangles
of the four completely miscible ternary subsystems. For symmetrical mixtures
of K components (identical chain lengths and interaction parameters) equations
are presented that allow the calculation of K-phase and (K - 1)-phase regions
for any value of K.

preprint number: 163