Flory-Huggins interaction constant

Here % is the Flory-Huggins interaction parameter and ( ), is the penetrant volume fraction. In order to use Eqs. (26)—(28) for the prediction of D, one needs a great deal of data. However, much of it is readily available. For example, Vf and Vf can be estimated by equating them to equilibrium liquid volume at 0 K, and Ku/y and K22 - Tg2 can be computed from WLF constants which are available for a large number of polymers [31]. Kn/y and A n - Tg can be evaluated by using solvent viscosity-temperature data [28], The interaction parameters, %, can be determined experimentally and, for many polymer-penetrant systems, are available in the literature. 

The Flory-Huggins interaction parameter, x Is the sum of enthalpic (xH) and entropic (x ) contributions to the polymer-solute interactions (28). xs is an emPitical constant related to the coordination of the polymer subunits (29). Chiou et al. (20) have selected a value of 0.25 for xs of humlc matter. From regular solution theory, xq is given by... 

In the above equation, % is the Flory-Huggins interaction parameter, R is the universal gas constant, 02a is the average volume fraction of polymer in the adsorbed layer, and 2b is the bulk polymer concentration. 

The terms between the brackets correspond to the osmotic contribution to the Gibbs free energy (AG), and they also constitute the standard expression for AG of the Flory-Huggins theory of polymer solutions [61], where < p is the volume fraction of polymer and the ratio of the equivalent number of molecular segments of solvent to polymer (usually expressed as the ratio of molar volumes of solvent and polymer). Xap is the Flory-Huggins interaction parameter of solvent and polymer and the last term of Equation 14.1 is the interfacial free energy contribution where y is the interfacial tension, the molar volume of solvent, and r the particle radius. T is temperature in Kelvin and R is the universal gas constant. 

Flory-Huggins interaction parameter a packing coefficient, medium viscosity initial viscosity, constant... 

This chapter has provided a range of mathematical models that can be used to characterize the effects of minor components on membrane performance. However, the quantity of good experimental data that can be used to fit these models remains quite limited. Good characterization of membrane performance in both pre-combustion and post-combustion flue gases will require accurate experimentally based determination of parameters such as Flory-Huggins interaction parameters, Langmuir constants and plasticization potentials. 

Ni is the number of monomers in chain i, and Vi is the volume of each monomer on chain i, 4>a is the volume fraction of component A in the mixture, v is an arbitrary reference volume, x is the Flory-Huggins interaction parameter, AGm is the free energy change on mixing per unit volume, k is the Boltzmann constant, and T is the absolute temperature. In this work the reference volume, v, is equal to 0.1 nm. ... 

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