Influence of solvent and non-solvent on polyimide asymmetric membranes formation in relation to gas permeation

Asymmetric 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FD A)-2-methyl-1, 3-phenylenediamine (mPDA) polyimide membranes were prepared by phase inversion process. Using different non-solvents and solvents, the correlation between membrane elaboration conditions acid final morphology a nd properties has been investigated. Equilibrium thermodynamics and diffusi on coefficients data were determined as a preliminary analysis in order to underline competitivity between thermodynamic and kinetic parameters. Scann ing electron microscopy and gas permeation experiments (CO2, N-2) were used for the determination of structure-permeability relationships. Sponge-like structure membranes and highest selectivity were obtained when using non-s olvent/solvent/6FDA-mPDA systems having important coagulation time. (C) 200 1 Elsevier Science B.V. All rights reserved.