Effect of polyether diamine on gas permeation properties of organic-inorganic hybrid membranes

Sol-gel derived organic-inorganic hybrid materials were prepared by reacting 3-isocyanatopro pyltriethoxysilane (IPTS) with diamines containing polyether segments. Composite membranes were obtained by casting the hybrid sols on microporous polysulfone substrates. The structural analysis of these materials was characterized by FT-IR and Si-29-NMR. Gas permeation properties of hybrid membranes were evaluated, and the effect of the structure and molecular weight of polyether diamine on gas permeation properties was studied. The permeability coefficients increase with increasing of molecular weight of poly(propylene glycol) bis(2-aminopropyl ether) (APPG) and poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether) (PAPE). The permeability coefficients of N-2, O-2, and CH4 for APPG2000 membrane are higher than those for PAPE2000. In contrast, the permeability coefficient of CO2 is higher for PAPE2000 membrane, because of strong affinity between CO2 molecules and ethylene oxide segments. The addition of TEOS into hybrid sol results in the decrease of gas permeability coefficients.