Highly asymmetric anionic membranes
AssigneeUSF Filtration and Separations Group, Inc.
InventorI-fan Wang
Life of this patent
Estimating the term…
Abstract
The present invention relates to anionically charge-modified membranes and methods of preparing such membranes. In one major aspect of the invention, the membranes are internally hydrophilic and formed from casting a film of a mixed polymer solution that includes an anionic agent.
Claims70
A polymer membrane having permanent internal anionic charges, cast from a solution or suspension comprising a sulfone polymer, an anionic charge-modifying agent, a nonsolvent, and a solvent, the membrane having a first surface and a second surface, each surface having pores thereon, the membrane also having a porous supporting structure between the first and second surface, wherein the porous supporting structure comprises a reticulated network of flow channels between the pores of the first surface and the second surface, wherein the anionic charge-modifying agent comprises 2-acrylamido-2-methylpropane sulfonic acid or 1-propanesulfonic acid 2-methyl-2-(1-oxy-2-propenyl amino.
A method of forming a polymer membrane having permanent internal anionic charges, the method comprising:
- providing a casting solution or suspension comprising a sulfone polymer, an anionic charge-modifying agent, a nonsolvent, and a solvent, wherein the anionic charge-modifying agent comprises 2-acrylamido-2-methylpropane sulfonic acid or 1-propanesulfonic acid 2methyl-2-(1-oxy-2-propenyl amino);
- casting the solution or suspension to form a thin film;
- coagulating the film in a quench bath;
- and
- recovering a polymer membrane having permanent internal anionic charges, the membrane having a first surface and a second surface, each surface having pores thereon, the membrane also having a porous supporting structure between the first and second surface, wherein the porous supporting structure comprises a reticulated network of flow channels between the pores of the first surface and the second surface.
A polymer membrane having permanent internal anionic charges, cast from a solution or suspension comprising a sulfone polymer, an anionic charge-modifying agent, a nonsolvent, and a solvent, the membrane having a first surface and a second surface, each surface having pores thereon, the membrane also having a porous supporting structure between the first and second surface, wherein the porous supporting structure comprises a reticulated network of flow channels between the pores of the first surface and the second surface, wherein the membrane is asymmetric, and wherein the pores of the first surface are at least about 5 times smaller than the pores at the second surface.
A method of forming a polymer membrane having permanent internal anionic charges, the method comprising:
- providing a casting solution or suspension comprising a sulfone polymer, an anionic charge-modifying agent, a nonsolvent, and a solvent;
- casting the solution or suspension to form a thin film;
- coagulating the film in a quench bath;
- and
- recovering a polymer membrane having permanent internal anionic charges, the membrane having a first surface and a second surface, each surface having pores thereon, the membrane also having a porous supporting structure between the first and second surface, wherein the porous supporting structure comprises a reticulated network of flow channels between the pores of the first surface and the second surface, wherein the membrane is asymmetric, and wherein the pores of the first surface are at least about 5 times smaller than the pores at the second surface.
Dependencies are inferred from the claim text.