Cobalt neutralized sulfo EPDM (Co (Ⅱ) S EPDM) ionomer has been synthesized by sulfonation and neutralization of EPDM. The oxygen permeability and O2/N2 permselectivity of Co (Ⅱ) S EPDM membrane were investigated. It was found that the membrane exhibited facilitated transport for molecular oxygen. This is suggested that a kind of polymer complexes was formed in the ionomer
which could bind molecular oxygen rapildy and reversibly through their other vacant coordination sites. The oxygen-binding evidence was given by ESR spectral change.