Grafted polysulfone membranes

Patent metadata

Field	Value
Publication number	US-2018185835-A1
Application number	US-201515738969-A
Country	US
Kind code	A1
Filing date	Nov 19, 2015
Priority date	Jun 26, 2015
Publication date	Jul 5, 2018
Grant date	—

Abstract

A polysulfone membrane is modified so that monomers are grafted onto the surface of the membrane. The polysulfone membranes can be grafted by contacting the membrane with a grafting solution and exposing the membrane to electromagnetic radiation, typically within the ultraviolet portion of the spectrum. The monomers that are grafted are typically anionic or cationic. The grafted membranes can be used for filtering impurities, such as positively and negatively charged particles, from a liquid. Anionic membranes provide improved filtration of negatively charged impurities, while cationic membranes provide improved filtration of positively charged impurities.

First claim

1 . A grafted polysulfone membrane comprising one or more monomers grafted onto one or more surfaces of the membrane, wherein the grafted polysulfone membrane has a water flow rate that is at least 75% of the water flow rate of an ungrafted polysulfone membrane.

2 . The grafted polysulfone membrane of claim 1 , wherein the grafted monomer is an anionic monomer.

3 . The grafted polysulfone membrane of claim 2 , wherein the anionic monomer is vinylsulfonic acid or vinylsulfonic acid sodium salt.

4 . The grafted polysulfone membrane of claim 2 , wherein the anionic monomer is one or more of 2-ethylacrylic acid, acrylic acid, 2-carboxyethyl acrylate, 3-sulfopropyl acrylate potassium salt, 2-propyl acrylic acid, 2-(trifluoromethyl)acrylic acid, methacrylic acid, 2-methyl-2-propene-1-sulfonic acid sodium salt, mono-2-(methacryloyloxy)ethyl maleate, and 3-sulfopropyl methacrylate potassium salt, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-methacrylamido phenyl boronic acid, vinyl sulfonic acid, and vinyl phosphoric acid.

5 . The grafted polysulfone membrane of claim 1 , wherein the grafted monomer is a cationic monomer.

6 . The grafted polysulfone membrane of claim 5 , wherein the cationic monomer is one or more of 2-(dimethylamino)ethyl hydrochloride acrylate, [2-(acryloyloxy)ethyl]trimethylammonium chloride, 2-aminoethyl methacrylate hydrochloride, N-(3-aminopropyl) methacrylate hydrochloride, 2-(dimethylamino)ethyl methacrylate hydrochloride, [3-(methacryloylamino)propyl]trimethylammonium chloride solution, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, acrylamidopropyl trimethylammonium chloride, 2-aminoethyl methacrylamide hydrochloride, N-(2-aminoethyl) methacrylamide hydrochloride, N-(3-aminopropyl)-methacrylamide hydrochloride, diallyldimethylammonium chloride, allylamine hydrochloride, vinyl imidazolium hydrochloride, vinyl pyridinium hydrochloride, and vinyl benzyl trimethyl ammonium chloride.

7 . The grafted polysulfone membrane of claim 5 , wherein the cationic monomer diallyldimethylammonium chloride.

8 . The grafted polysulfone membrane of claim 1 , wherein the grafted polysulfone membrane has a dye binding capacity between about 1 μg/cm 2 and about 5 μg/cm 2 .

9 . (canceled)

10 . (canceled)

11 . The grafted polysulfone membrane of claim 1 , wherein the brittleness of the grafted polysulfone membrane in the machine direction does not exceed the brittleness of the ungrafted polysulfone membrane in the machine direction, the crossweb direction or both by more than 30%.

12 . (canceled)

13 . The grafted polysulfone membrane of claim 1 , wherein the grafted polysulfone membrane has a bubble point between about 65 psi and about 75 psi when determined by an ethoxy-nonafluorobutane bubble point test.

14 . A method of making a grafted polysulfone membrane, comprising:
a) contacting the polysulfone membrane with an alcohol solution comprising benzophenone; b) contacting the polysulfone membrane with an aqueous exchange solution; c) contacting the polysulfone membrane with an aqueous grafting solution comprising:
i) an anionic or cationic monomer;
ii) sodium sulfate; and
iii) sodium persulfate; and
d) exposing the polysulfone membrane to electromagnetic radiation, thereby resulting in a grafted polysulfone membrane.

15 . The method of claim 14 , wherein the anionic monomer is one or more of 2-ethylacrylic acid, acrylic acid, 2-carboxyethyl acrylate, 3-sulfopropyl acrylate potassium salt, 2-propyl acrylic acid, 2-(trifluoromethyl)acrylic acid, methacrylic acid, 2-methyl-2-propene-1-sulfonic acid sodium salt, mono-2-(methacryloyloxy)ethyl maleate, and 3-sulfopropyl methacrylate potassium salt, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-methacrylamido phenyl boronic acid, vinyl sulfonic acid, and vinyl phosphonic acid.

16 . The method of claim 14 , wherein the anionic monomer is vinylsulfonic acid or vinylsulfonic acid sodium salt.

17 . The method of claim 14 , wherein the cationic monomer is one or more of 2-(dimethylamino)ethyl hydrochloride acrylate, [2-(acryloyloxy)ethyl]trimethylammonium chloride, 2-aminoethyl methacrylate hydrochloride, N-(3-aminopropyl) methacrylate hydrochloride, 2-(dimethylamino)ethyl methacrylate hydrochloride, [3-(methacryloylamino)propyl]trimethylammonium chloride solution, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, acrylamidopropyl trimethylammonium chloride, 2-aminoethyl methacrylamide hydrochloride, N-(2-aminoethyl) methacrylamide hydrochloride, N-(3-aminopropyl)-methacrylamide hydrochloride, diallyldimethylammonium chloride, allylamine hydrochloride, vinyl imidazolium hydrochloride, vinyl pyridinium hydrochloride, and vinyl benzyl trimethyl ammonium chloride.

18 . The method of claim 14 , wherein the cationic monomer is diallyldimethylammonium chloride.

19 . The method of claim 14 , wherein the alcohol solution comprises isopropyl alcohol.

20 . (canceled)

21 . (canceled)

22 . The method of claim 14 , wherein the aqueous exchange solution comprises sodium persulfate.

23 . The method of claim 14 , wherein the aqueous solution comprises one or more of sodium sulfate and sodium persulfate.

24 . The method of claim 14 , wherein the alcohol solution comprises isopropyl alcohol, and wherein the aqueous exchange solution comprises sodium sulfate and sodium persulfate.

25 . The method of claim 14 , wherein the electromagnetic radiation has a wavelength between about 200 nm and about 600 nm.

26 . A method of removing an impurity from a liquid, comprising contacting the liquid with a polysulfone membrane grafted according to claim 1 .

Assignees

• Entegris Inc

Inventors

• Jaber Jad Ali
• Gjoka Alketa
• Ly Saksatha

Classifications

• B01D71/68 Primary

  Polysulfones; Polyethersulfones · CPC title

• B01D2325/14

  Membrane materials having negatively charged functional groups · CPC title

• B01D2323/385

  involving radiation · CPC title

• B01J41/13

  obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds · CPC title

• B01D2323/36

  Introduction of specific chemical groups · CPC title