Polymer membranes on the basis of polyvinylidene fluoride, a process for the production thereof and their use
First Claim
1. A process for the production of polymer membranes on the basis of polyvinylidene fluoride (PVDF), wherein a homogeneous solution L1 containinga) 5 to 30% by weight of PVDF andb) 0.01 to 30% by weight of at least one sulfonic acid (PEEKSO3 H) salt obtained by sulfonating the polyetheretherketone (PEEK, poly(oxy-1,4-phenyleneoxy-1,4-phenylene-carbonyl-1,4-phenylene)) of formula (I)
is converted into a membrane by known techniques, and wherein the surface of the membrane is subsequently coated with a film by treating the membrane with a methanolic solution L2 containing 0.1 to 5% by weight of at least one sulfonic acid PEEKSO3 H or salt.
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Abstract
The present invention relates to polymer membranes on the basis of polyviidene fluoride (PVDF), a process for the production thereof and their use for ultrafiltration. The membranes are produced according to known techniques from homogeneous solutions containing 5 to 30% by weight of PVDF and 0.01 to 30% by weight of sulfonic acids and/or their salts, obtainable by sulfonation of the polyetheretherketones of formula (I) and/or subsequent neutralization of the sulfonic acids. The membranes are then treated with methanolic solutions containing 0.1 to 5% by weight of the above-mentioned sulfonic acids and/or their salts. This process supplies membranes having excellent hydrophilic properties, high thermal and mechanical stabilities and high trans-membrane flows.
--(--O--p--C.sub.6 H.sub.4 --O--p--C.sub.6 H.sub.4 --CO--p--C.sub.6 H.sub.4
--)n -- (I)
-
Citations
35 Claims
- 1. A process for the production of polymer membranes on the basis of polyvinylidene fluoride (PVDF), wherein a homogeneous solution L1 containing
a) 5 to 30% by weight of PVDF and b) 0.01 to 30% by weight of at least one sulfonic acid (PEEKSO3 H) salt obtained by sulfonating the polyetheretherketone (PEEK, poly(oxy-1,4-phenyleneoxy-1,4-phenylene-carbonyl-1,4-phenylene)) of formula (I) - space="preserve" listing-type="equation">--(--O--p--C.sub.6 H.sub.4 --O--p--C.sub.6 H.sub.4 --CO--p--C.sub.6 H.sub.4 --).sub.n -- (I)
is converted into a membrane by known techniques, and wherein the surface of the membrane is subsequently coated with a film by treating the membrane with a methanolic solution L2 containing 0.1 to 5% by weight of at least one sulfonic acid PEEKSO3 H or salt. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
- 18. The process according to claim 1 wherein the membrane is precipitated at temperatures ranging between -20°
- C. and +50°
C.
- 19. The process according to claim 18 wherein water is used as the precipitating agent for the membrane.
- 20. The process according to claim 18 wherein a water/solvent mixture is used as the precipitating agent for the membrane.
- 21. The process according to claim 20, wherein a dipolar, aprotic solvent is used as the solvent.
- 22. The process according to claim 21, wherein the solvent used is at least one of dimethylformamide, N-methylpyrrolidone, dimethylacetamide and dimethylsulfoxide.
- 23. The process according to claim 1 wherein a water/solvent mixture having 0 to 50% by weight of solvent is used.
- 24. The process according to claim 23, wherein a water/solvent mixture having 5 to 50% of solvent is used.
- 25. The process according to claim 1 wherein methanolic solution L2 contains 0.5 to 2% by weight of the sulfonic acid PEEKSO3 H or salt.
- 26. The process according to claim 1 wherein the methanolic solution L2 is sprayed onto the polymer membrane.
- 27. The process according to claim 1 wherein the methanolic solution L2 is brushed onto the polymer membrane.
- 28. The process according to claim 1 wherein the polymer membrane is immersed in the methanolic solution L2.
- 29. The process according to claim 1 wherein the sulfonic acid PEEKSO3 H or salt, present on the membrane surface, is cross-linked with Ca++ ions.
- 30. Polymer membrane produced according to a process as defined in claim 1.
- 31. The polymer membrane according to claim 30, which is a flat membrane.
- 32. Polymer membrane according to claim 30, which is a tubular membranes.
- 33. Polymer membrane according to claim 30, which is a capillary membranes.
- 34. Polymer membrane according to claim 30, which is a hollow fiber.
- 35. In a method of ultrafiltration in which the material to be ultrafiltered is passed through an ultrafiltration membrane, the improvement which comprises employing the polymer membrane of claim 30 as the ultrafiltration membrane.
Specification