Liquid–liquid phase separation in multicomponent polymer solutions. II. The critical state
Article first published online: 10 MAR 2003
Copyright © 1968 John Wiley & Sons, Inc.
Journal of Polymer Science Part A-2: Polymer Physics
Volume 6, Issue 2, pages 325–347, February 1968
How to Cite
Koningsveld, R. and Staverman, A. J. (1968), Liquid–liquid phase separation in multicomponent polymer solutions. II. The critical state. J. Polym. Sci. A-2 Polym. Phys., 6: 325–347. doi: 10.1002/pol.1968.160060202
- Issue published online: 10 MAR 2003
- Article first published online: 10 MAR 2003
- Manuscript Revised: 26 MAY 1967
- Manuscript Received: 7 FEB 1967
Theoretical and experimental evidence is put forward to prove that the determination of the phase-volume ratio as a function of temperature and concentration is a sensitive and simple means of determining the liquid–liquid critical state. Knowledge of the critical conditions permits very accurate calculations of the interaction parameter g in the free-energy function. In experiments with polystyrene–cyclohexane, g was found to depend on the concentration. The value of g and its concentration dependence agree very well with the results of osmotic measurements by Rehage and Palmen. In experiments with polyethylene–diphenyl ether, g proved to be independent of concentration in the range of measurement. The temperature function was found to be: g = −0.6086 + 482.2/T (at 137–148°C.). Gibbs' expressions for the critical conditions were worked out for a free-energy relation in the form of an extended Flory-Huggins function.