Methods to determine solubility parameters of polymers at high temperature using inverse gas chromatography

Abstract

Experimental values of Flory-Huggins parameters, , between polymers and probes, are frequently used to determine the solubility parameters of the polymers by the method of DiPaola-Baranyi and Guillet. The solubility parameters of probes were usually estimated by using heat of vaporization. When is measured at a temperature near the critical temperature of the probes and used to determine the solubility parameter of polymers, the departure of enthalpy of the probe vapor from the ideal gas state should be considered. This study discussed the method to make the correction and its effect on the determination solubility parameter of polymers. Without correction in the vapor phase enthalpy, the solubility parameters of the probes and polymer tend to be underestimated and the error increases when the critical temperature is approaching. Analytical expressions for the effect of correction on the solubility parameter of probes and parameters of polymers were derived. By use of probes with a range of solubility parameters on both sides of the solubility parameter of polymers, the correlation between parameters of polymers was shown to be reduced.

Multiparameter solubility model of fullerene C60

“…In previous studies a method to examine the confidence interval for parameters of the one-dimensional solubility parameter model was discussed [34,35]. The method used a linearized expression for the sum of error square around the optimum values of parameters.…”

“…By using a linearization method around the optimum values of the five parameters, the approximate joint confidence contour of Eq. (10) can be expressed as a quadratic form using the relative values of λ, τ, q 2 , α, and β to their optimum values as the variables [34][35][36]:…”

Solubility and diffusivity of solvents and nonsolvents in poly(methyl methacrylate co butyl methacrylate)

“…(6). The effect of high temperature on cohesive energy density [ H v /V 1 ], and the need to include vapor phase non ideality correction was explained by Huang et al [19] to estimate the solubility parameter. At temperatures near the critical temperature, the density of the vapor phase gradually increases, and the departure of saturated vapor from the ideal gas becomes significant and needs to be included in the definition of cohesive energy density.…”

“…At temperatures near the critical temperature, the density of the vapor phase gradually increases, and the departure of saturated vapor from the ideal gas becomes significant and needs to be included in the definition of cohesive energy density. At high temperatures, the saturated vapor is in an high temperature and high density state and its internal energy departure from the ideal state (E o − E) vap , should be combined with the heat of vaporization for the calculation of solubility parameter of the solvent, δ * 1 (with vapor phase non ideality correction) [19]. The equation is;…”

“…Again, the correction of vapor phase non ideality gave higher solubility parameter for the polymer. Without the correction, the solubility parameters of solvent and polymer tended to be underestimated [19]. Therefore, at high temperatures, vapor phase non ideality should be taken into account for the calculation of the solubility parameter of the solvent.…”