Permeation modified asymmetric gas separation membranes having graded density skins
US4728346A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 15, 1986 |
| Grant date | Mar 1, 1988 |
| Priority date | — |
| Expiry date | Aug 15, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D69/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Asymmetric gas separation membranes having graded density skins and macrovoid-free morphology comprised of glassy, hydrophobic polymers which when contacted on the graded density skin surface with an effective amount of permeation modifier and a coating in occluding contact, exhibit permeation selectivities greater than the intrinsic permeation selectivities for at least one gas of a gaseous mixture than a bulk sample of the polymers. The permeation modified membranes have increased free volume as evidenced by the membrane first heat T.sub.g which is greater than the T.sub.g of the bulk sample of the glassy, hydrophobic polymers; however the permeation modified membranes having an effective amount of permeation modifier added in non-uniform mode are achieved without significant loss in the physical properties of the membrane, including T.sub.g.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.