| 摘要 |
Process for producing integrally asymmetrical hydrophobic polyolefinic membranes with a separation layer, in particular for gas exchange, via thermally induc ed liquid- liquid phase separation. A solution of at least one polyolefin in a solvent system con- sisting of a compound A and a compound B is extruded to form a shaped object . Compound A is a strong solvent and compound B a weak non-solvent for the pol y- mer. After leaving the die, the shaped object is cooled using a solid or liquid cooling medium, which does not dissolve the polymer and does not react chemically wi th it, until the phase separation and solidification of the high-polymer-content phase take place. The integrally asymmetrical membrane producible in this manner has a poros- ity of greater than 30% to 75% by volume, a sponge-like, open-pored, microporous support layer without macrovoids and on average isotropic pores, a separatio n layer on at least one of its surfaces with pores <100 nm, if any, and a gas separation fac- tor a(CO2/N2) of at least 1. The membrane is preferably used for blood oxygenation.
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