2011 Annual Meeting

(699a) Prediction of Mixed Gas Solubility-Selectivity In Glassy Polymers

Authors

Matteo Minelli - Presenter, University of Bologna
Simone Campagnoli - Presenter, University of Bologna
Ferruccio Doghieri - Presenter, University of Bologna
Giulio C. Sarti - Presenter, University of Bologna


The knolwedge of mixed gas solubility selectivity in glassy polymers is of fundamental importance for the development gas separation membranes. For rubbery polymers the usual equation of state (EoS) models can be applied to calculate multiple gas solubility in the equilibrium phases; for the case of glassy polymers the same thermodynamic tool cannot be used. The approach called Non Equilibrium Thermodynamics of Glassy Polymers (NET-GP) [1], coupled to the Lattice Fluid (LF) model for the representation of substances [2,3], was applied to the solubility of gases and vapors in glassy polymers in different conditions .

Here the same approach is applied to the modeling of multicomponent gas solubility in a pure glassy polymeric matrix, to predict the solubility of binary gas mixtures in pure glassy polymers as CH4/CO2 in Poly(2,6-dimethylphenyleneoxide) (PPO), C2H4/CO2 and N2O/CO2 in poly(methylmetacrylate) (PMMA) for which experimental data are available [4-5] and it is observed that the solubility of mixed gases differ significantly from the corresponding pure component values. In the calculations, the gas-polymer binary energetic parameters kij are adjusted on the solubility data of the single gas in the polymer, and the gas-gas binary interaction parameter is considered zero in view of the high dilution of gaseous components in the polymer.The swelling induced by the gaseous mixture in the polymer is assumed to follow a simple additive rule based on the penetrant partial pressure in the external gaseous phase.

The model allows to predict the experimental behavior to an accuracy of about 10%.

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[3]           F. Doghieri, G. C. Sarti, Macromolecules 29 (1996) 7885.

[4]           E.S. Sanders, W.J. Koros, J. Polym. Sci.: Polym. Phys. Ed. 24 (1986) 175.

[5]           B.J. Story, W.J. Koros, J. Membr. Sci. 67 (1992) 191.