Membranes containing microporous structure
US4775474A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 1, 1986 |
| Grant date | Oct 4, 1988 |
| Priority date | — |
| Expiry date | Dec 1, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2325/022
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Asymmetric membranes are prepared by treating a major surface of a glassy polymer composition to render the surface resistant to solvent crazing and then contacting the glassy polymer composition with a crazing solvent. The crazing solvent permanently deforms the glassy polymer composition by forming a microporous structure on the untreated surface. The treated surface becomes the dense, discriminating layer of the membrane which achieves desirable permeation selectivity. The methods of treatment are (1) crosslinking, (2) providing an agent which renders the surface resistant to crazing, and (3) providing an agent which reacts with the surface. Additionally, the glassy polymer composition can be crosslinked before or after it is crazed to increase the mechanical strength of the membrane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.