OXYGEN NITROGEN TRANSPORT IN GLASSY-POLYMERS WITH OXYGEN-BINDING PENDENT GROUPS

Polymeric membranes exhibit an inverse relation between O2/N2 selectivity and O2 permeability. O2 carriers can be used to cross this selectivity barrier. O2/N2 selectivity was increased by incorporating oxygen-binding cobalt complexes into glassy polymers. The O2 carriers have been incorporated both by blending with the polymer and by attaching to the polymeric backbone as pendent groups. Polymers with O2 carriers as pendent groups showed better O2/N2 selectivities. The improved selectivity results from facilitation of O2 and inhibition of N2 transport. Oxygen selectivity increases with increasing content of the cobalt complex and decreasing O2 partial pressure. The O2 transport in these polymers has been interpreted using the dual-mode model. O2 bound to carrier site diffuses slowly but has very high solubility coefficient. These membranes have a life time problem. O2 selectivity decreases with increasing O2 exposure time. More stable O2 carriers are required to make these membranes commercially viable. © 1990.