Method of making single film, high performance bipolar membrane
US4140815A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1977 |
| Grant date | Feb 20, 1979 |
| Priority date | — |
| Expiry date | Apr 26, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2353/02
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Novel single film bipolar membranes, of substantially improved efficiency and durability, i.e. having an ion selectivity above 80% in an electrolyte medium of about one mole, are prepared from pre-swollen films containing a relatively high amount, i.e. at least 15% of an insoluble cross-linked aromatic polymer. Under controlled conditions, highly dissociable cationic-exchange groups are chemically bonded to the aromatic nuclei to a desired depth of the film from one side only; subsequently, highly dissociable anion-exchange groups are chemically bonded to the unreacted aromatic nuclei on the other side of the film. The functionalized, densely structured single film ion exchange membrane undergoes negligible degradation, is blister free, and is uniquely suited for electrodialysis particularly water-splitting operations due to its low electrical resistance and low salt leakage. The membrane operates with improved current efficiencies at both high electrolyte concentrations and high current densities, for time periods not previously achievable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.