Hydrophilic polyvinylidene fluoride membranes
AssigneeSartorius AG
InventorsDaniel J. Brose, Dwayne T. Friesen, James R. Lowell, Jr., Scott B. McCray, John M. Radovich
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Abstract
Improved methods of rendering PVDF membranes hydrophilic are disclosed.
Claims10
A method of rendering hydrophilic a non-skinned, substantially isotropic membrane fabricated from a polymer that is at least 90 wt % of a polymer selected from the group consisting of polyvinylidene fluoride and a copolymer of vinylidenefluoride and hexafluoropropylene, comprising the following steps:
- (a) wetting said membrane with water;
- (b) conducting a dithionate reduction of said membrane by contacting the same with a solution of NaOH and Na.sub.2 S.sub.2 O.sub.4 and heating the same;
- (c) rinsing said membrane with water;
- (d) contacting said membrane with a bleach solution and heating the same;
- (e) rinsing said membrane with water;
- and
- (f) drying said membrane.
A method of rendering hydrophilic a non-skinned, substantially isotropic membrane fabricated from a polymer that is at least 90 wt % of a polymer selected from the group consisting of polyvinylidene fluoride and a copolymer of vinylidenefluoride and hexafluoropropylene, comprising the following steps:
- (a) wetting said membrane with water;
- (b) conducting a glucosamine reduction of said membrane comprising the steps of
- (i) contacting said membrane with a caustic solution and heating,
- (ii) rinsing said membrane with water, and
- (iii) contacting said membrane with an alkaline solution of glucosamine and heating;
- (c) rinsing said membrane with water;
- (d) contacting said membrane with a bleach solution and heating the same;
- (e) rinsing said membrane with water;
- and
- (f) drying said membrane.
A method of rendering hydrophilic a non-skinned, substantially isotropic microfiltration membrane fabricated from a polymer that is at least 90 wt % of a polymer selected from the group consisting of polyvinylidene fluoride and a copolymer of vinylidenefluoride and hexafluoropropylene, comprising the following steps:
- (a) wetting said membrane with water;
- (b) conducting an oxidation step comprising the steps of
- (i) contacting said membrane with a caustic solution and heating,
- (ii) rinsing said membrane with water, and
- (iii) contacting said membrane with a weakly acidic solution of hydrogen peroxide and heating;
- (c) rinsing said membrane with water;
- (d) contacting said membrane with a bleach solution and heating the same;
- (e) rinsing said membrane with water;
- and
- (f) drying said membrane.
Dependencies are inferred from the claim text.