Prediction of Initial Miscibility for Ternary Polyurethane Reaction Mixtures on Basis of Solubility Parameters and Flory–Huggins Theory

A straightforward approach to predict miscibility for bi‐soft segment polyurethane reaction mixtures is developed. Flory–Huggins theory and solubility‐parameter‐based interaction parameters are applied for numerical estimation of binodal compositions. Experimental and predicted findings for polyether polyol mixtures are in excellent agreement. The content of diisocyanate plays a critical role regarding the miscibility of reaction mixtures.