Permea, Inc.

Robert E Kesting

Raymond F Malon

Milton K Murphy

Clint A Cruse

Alfred K Fritzsche

Alan C Handerman

Alan C Handermann

Asymmetric gas separation membranes having graded density skins and macrovoid-free morphology comprised of glassy, hydrophobic polymers are disclosed which are effective for separation gases with significante increases in permeation while maintaining equal or greater separation electivity. The membranes have increased free volume and the graded density skin exhibits a density gradient which becomes more dense with increasing proximity to the surface, the membrane effectively decouples the interdependency between permeability and separation selectivity.

Asymmetric gas separation membranes having graded density skins

A process for forming high free volume, asymmetric gas separation membranes having graded density skins and macrovoid-free morphology from a solvent system comprising a Lewis acid, Lewis base, and a Lewis acid:base complex which dissolve hydrophobic polymers. The dopes have high total solids, high viscosity and low coagulation (g) values which enhance rapid gelation without the formation of macrovoids and which minimize densification. The dope solvent system complexes are readily disassociated by the coagulation medium and the component molecules are miscible in the medium which provides for rapid desolvation of the formed membrane thus providing a membrane having low residual solvent retention.

Process for forming asymmetric gas separation membranes having graded

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Elsenfeld, Germany

Robert E Kesting