Method of making polyvinylidene fluoride membrane
US5489406A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 8, 1992 |
| Grant date | Feb 6, 1996 |
| Priority date | — |
| Expiry date | Dec 8, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2327/16
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method of making a porous polymeric material by heating a mixture comprising polyvinylidene fluoride and a solvent system initially comprising a first component that is a latent solvent for polyvinylidene fluoride and a second component that is a non-solvent for polyvinylidene fluoride wherein, at elevated temperature, polyvinylidene fluoride dissolves in the solvent system to provide an optically clear solution. The solution is then rapidly cooled so that non-equilibrium liquid-liquid phase separation takes place to form a continuous polymer rich phase and a continuous polymer lean phase with the two phases being intermingled in the form of bicontinuous matrix of large interfacial area, and cooling is continued until the polymer rich phase solidifies. The polymer lean phase is removed from the solid polymeric material. A porous material so prepared is characterised by a lacey or filamentous structure consisting of a plurality of polymer strands (1) connected together at a number of locations (2) spaced apart along each strand.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.