Estimation of χ Parameters from Phase Diagrams
Based on cloud point data for a polystyrene–polybutadiene mixture exhibiting a UCST-type phase diagram, the Flory–Huggins theory was used to estimate χ parameters. Since the system shows weak concentration dependence, a simplified formula was applied, and calculations were performed with J-OCTA’s optional tool. Coexistence and spinodal curves corresponding to experimental values were obtained.
Use Cases Highlights
- Application of Flory–Huggins theory
- Estimation of coexistence and spinodal curves from experimental data
- Capability to consider concentration dependence
Comparison between phase diagrams and estimated results
Coexistence and spinodal curves obtained from volume fraction–temperature relationships are shown. χ parameters estimated by Flory–Huggins theory are consistent with experimental values.

Coexistence curve and spinodal curve against experimental data
Reference
[1] R.J.Roe, W. C. Zin, Macromolecules,13, 1221 (1980)
Details of analysis
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