High temperature membrane
US4640901A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 18, 1985 |
| Grant date | Feb 3, 1987 |
| Priority date | — |
| Expiry date | Mar 18, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2111/00801
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention concerns a method of making a silica-based membrane comprising the steps of: PA0 (1) pyrolyzing the material made of one of the class comprising polysilicone rubber, polysilane and polysiloxane at a temperature range of about 500.degree. C. to about 1000.degree. C. for about 2 hours (minimum) in an inert atmosphere; and PA0 (2) oxidizing the pyrolyzed material at a sufficient temperature range of about 300.degree. C. to about 1000.degree. C. to crosslink the material with oxygen. The membrane typically has a B.E.T. surface-area measurement of about 220 m.sup.2 /g which indicates a highly porous membrane--about 40 to 70% porosity. The present invention may also be characterized by producing a pyrolyzed membrane by the method described above, and coating the membrane with silicon material to fill in the large micropores, and repyrolyzing the coated membrane to produce a membrane having extremely small micropores to assure that such gases as hydrogen and helium can be separated by the membrane product of the present invention to a high level of selectivity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.