Method of making a dope comprising hydrophilized PVDF and .alpha.-alumina, and a membrane made therefrom
US6024872A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 14, 1999 |
| Grant date | Feb 15, 2000 |
| Priority date | — |
| Expiry date | May 14, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/249979
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A filtration membrane for micro- or ultra-filtration is formed from a complex of PVDF and calcined .alpha.-alumina (".alpha.-Al") particles, in which complex the particles are reacted and dispersed. The suspended complex is then mixed with a hydrophilic polymer such as polyvinyl alcohol (40%-90% hydrolyzed) referred to herein as HPVA, which reacts with the complex imparting hydrophilicity to the polymer. The novel membrane provides about 50% higher specific flux than a membrane made with the same polymer but without the .alpha.-Al particles. Unexpectedly, the net flux is improved by treating the membrane with a solution of sodium hypochlorite which fails to remove the HPVA from the novel membrane but does remove it from the prior art membrane which does not contain the .alpha.-Al. The preferred membrane comprises a macroporous support coated on its outer surface with a thin tubular asymmetric semipermeable film of polymer containing less than about 50% by weight of .alpha.-Al particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.