Oxygen enriching property and stability of the blend membranes, 10-45 mu m
thick, fabricated from ethyl cellulose, cellulose nitrate, cellulose diacet
ate, and cellulose triacetate, with thermotropic cholesteric or nematic liq
uid crystals (LC). such as cholesteryl oleyl carbonate, p-heptyl-p'-cyanobi
phenyl, p-pentylphenol-p'-methoxybenzoate, benzoate containing liquid cryst
al mixture, and triheptyl cellulose, were studied by a variable volume meth
od. The membranes with 1.5-4 wt% LCs showed the maximum oxygen-enriching ab
ility in the temperature range of their LC phase. The oxygen-enriched air f
lux Q(OEA) and the oxygen concentration Y-O2 increased simultaneously as th
e operating pressure increased. The 30 mu m-thick triheptyl cellulose-ethyl
cellulose (8/92) homogeneous membrane exhibited almost constant oxygen- en
riching efficiencies of Q(OEA) 1.0 x 10(-4) ml(STP)/s . cm(2) and Y-O2 40%
at 30 degrees C and 0.41 MPa in a single step for a 35 day operating time.
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