Flory–Huggins Parameters for Thiol-ene Networks Using Hansen Solubility Parameters

Thiol-ene networks based on polar and nonpolar monomers at various crosslinking densities were subjected to swelling in organic solvents to measure the Flory–Huggins interaction parameter. To the best of our knowledge, this is the first example of Flory–Huggins measurements for thiol-ene networks in organic media. Experimentally determined values were compared to those predicted using the Hansen solubility parameter approach with the assistance of the HSPiP software, which is used industrially to determine the miscibility. It was shown that the polymer suite in this software does not adequately account for thioether bonds by underpredicting the dispersive Hansen parameter by roughly 5 MPa0.5 when corrected to experimental thiol-ene swelling data. Even with corrections for thioether bonds, HSPiP and Hansen solubility parameters, in general, lack the ability to account for structural factors that impact polymer–solvent interaction parameters, especially for crosslinked polymer networks.