Prediction of Initial Miscibility for Ternary Polyurethane Reaction Mixtures on Basis of Solubility Parameters and Flory–Huggins Theory. Issue 5 (29th December 2017)

• Record Type: Journal Article
• Authors: Wenning, Christian; Barbe, Stéphan; Achten, Dirk; Schmidt, Annette M.; Leimenstoll, Marc C.
• Is Part Of: Macromolecular chemistry and physics. Volume 219:Issue 5(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-12-29
• Subjects: Flory–Huggins theory -- miscibility prediction -- phase diagram -- polyurethanes -- solubility parameter; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.201700544
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract: The initial miscibility in bi‐soft segment polyurethane reaction mixtures is investigated on the basis of Flory–Huggins (FH) theory and solubility parameters (SPs). Different group contribution theories are applied to estimate the SPs of polyether polyol (PEP) structures and 1, 6‐hexamethylene diisocyanate (HDI). The PEP structure comprising starter molecule, ethylene oxide/propylene oxide moieties, and end‐functional hydroxyl groups is considered in the calculations. Binodal curves are determined computationally for binary PEP mixtures as well as for a ternary mixture consisting of HDI and a binary mixture of partially miscible PEPs. The computed phase equilibria are found to be in good agreement to experimental cloud points and binodal compositions. The prediction of miscibility for practically relevant ternary polyurethane systems on the basis of FH theory and SPs is thus feasible. Additionally, the study demonstrates that HDI is acting as a compatibilizer for partially miscible PEPs in the initial reaction mixture. Abstract : 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.