Method for preparing nanoporous polysulfone-based polymers

Abstract

The present invention relates to a method for preparing nanoporous polysulfone-based polymers, including: a copolymer of a polysulfone polymer and a polar polymer is immersed into a compound swelling agent, and maintained for at least 1 minute above room temperature; the compound swelling agent is a solvent pair composed of the mixture of solvent A and solvent B; the solvent A has high affinity with the polysulfone polymer; and the solvent B has high affinity with the polar polymer; the treated copolymer is taken out from the compound swelling agent and then dried to remove the solvent to obtain the nanoporous polysulfone-based polymers.

Claims

1. A method for preparing nanoporous polysulfone-based polymers, the steps comprising: 1) immersing a copolymer of a polysulfone polymer and a polar polymer into a compound swelling agent, and maintaining this for at least 1 minute above room temperature; the compound swelling agent is a solvent pair composed of the mixture of solvent A and solvent B; the solvent A has high affinity with the polysulfone polymer; and the solvent B has high affinity with the polar polymer; 2) taking the copolymer treated in Step 1) out from the compound swelling agent and then drying it to remove the solvent to obtain the nanoporous polysulfone-based polymers.

2. The method according to claim 1, wherein the polar polymer mentioned in Step 1) is a water-soluble or alcohol-soluble polymer.

3. The method according to claim 1, wherein in the copolymer of the polysulfone polymer and the polar polymer mentioned in Step 1), the volume of the polar polymer accounts for 5-40% of the entire copolymer volume.

4. The method according to claim 1, wherein the solvent A in the compound swelling agent mentioned in Step 1) is any one selected from the group consisting of acetic acid, N,N-dimethylformamide (DMF), N,N-dimethyl acetamide (DMAc), dimethyl sulfoxide (DMSO), acetone, methyl ethyl ketone or acetonitrile or a mixture of any two or more thereof.

5. The method according to claim 1, wherein the solvent B in the compound swelling agent mentioned in Step 1) is any one selected from the group consisting of water, methanol, ethanol, isopropanol, n-hexanol or methyl formate or a mixture of any two or more thereof.

6. The method according to claim 1, wherein the solvent A in the compound swelling agent mentioned in Step 1) is any one of acetic acid, DMAc, DMSO or acetone; and the solvent B is any one of water, ethanol, isopropanol or n-hexanol.

7. The method according to claim 1, wherein the volume ratio of solvent A and B in the compound swelling agent mentioned in Step 1) is controlled between 5:95 and 95:5.

8. The method according to claim 1, wherein the compound swelling agent mentioned in Step 1) is a solvent pair of acetone and ethanol mixed in a volume ratio of 20:80, a solvent pair of DMF and water mixed in a volume ratio of 10:90, a solvent pair of acetic acid and isopropanol mixed in a volume ratio of 15:85, a solvent pair of DMSO and n-hexanol mixed in a volume ratio of 10:90, or a solvent pair of DMAc and ethanol mixed in a volume ratio of 5:95.

9. The method according to claim 1, wherein the temperature mentioned in Step 1) is controlled between 30 and 80 C.; the mentioned time is controlled from 1 minute to 24 hours.

10. The method according to claim 1, wherein before the drying mentioned in Step 2), first place the copolymer taken out from the compound swelling agent into a low boiling point solvent to be substituted and then further remove the solvent remaining in the copolymer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a scanning electron micrograph of a nanoporous polysulfone-based copolymer prepared with the method described in Implementation Case 1.

(2) FIG. 2 is the comparison of the appearance and shape of nanoporous polysulfone bulk materials prepared with the method described in Implementation Case 2 before and after solvent treatment.

(3) FIG. 3 is a scanning electron micrograph of the inside of a nanoporous polysulfone bulk material prepared with the method described in Implementation Case 2.

(4) FIG. 4 is a scanning electron micrograph of a nanoporous polysulfone bulk material prepared with the method described in Contrast Example 2.

DESCRIPTION OF THE EMBODIMENTS

(5) Implementation Case 1

(6) A method for preparing nanoporous polysulfone-based polymers, whose steps include:

(7) 1) The block copolymer film of polysulfone and PEG having a PEG volume ratio of 20% was immersed in an ethanol/acetone solvent pair (having an acetone volume ratio of 20%) at 70 C. for 5 hours;

(8) 2) The copolymer film was taken out from the solvent and dried at 30 C. for 6 hours to obtain a nanoporous polymer film.

(9) The porous polymer obtained in the Implementation Case was characterized by the scanning electron microscopy, as shown in FIG. 1. The dense polymer before being treated with the ethanol/acetone solvent pair has been transformed into a highly porous structure, the pores are connected to each other, and the pore diameter is less than 100 nm. At the same time, the water contact angle of the surface of the copolymer film was reduced from 85 before ethanol treatment to 50 after the treatment, indicating that the obtained nanoporous material has good hydrophilicity.

(10) Implementation Case 2

(11) A method for preparing nanoporous polysulfone-based polymers, whose steps include:

(12) 1) The graft copolymer bulk of polysulfone and PEG having a PEG volume ratio of 35% was immersed in a water/DMF solvent pair (having a DMF volume ratio of 10%) at 60 C. for 24 hours;

(13) 2) The copolymer film was taken out from the solvent and dried at 60 C. for 2 hours to obtain the nanoporous polymer bulk material.

(14) In the Implementation Case, after treatment with the said water/DMF solvent pair, the copolymer was turned to milky white and its volume was increased, but its initial structure was basically maintained, as shown in FIG. 2. The bulk treated with the solvent pair was cut open, and its connected nanopores were observed with the scanning electron microscopy. This proves that the entire bulk material has produced pores, as shown in FIG. 3.

(15) Implementation Case 3

(16) A method for preparing nanoporous polysulfone-based polymers, whose steps include:

(17) 1) The random copolymer granule of polysulfone and PVP having a PVP volume ratio of 40% was immersed in an isopropyl alcohol/acetic acid solvent pair (having an acetic acid volume ratio of 20%) at 50 C. for 0.1 hours;

(18) 2) The copolymer granule was taken out from the solvent and dried at 40 C. for 10 hours to obtain the nanoporous polymer granular material.

(19) Implementation Case 4

(20) A method for preparing nanoporous polysulfone-based polymers, whose steps include:

(21) 1) The random copolymer film of polyphenylene sulfide and PEG having a PEG volume ratio of 5% was immersed in a n-hexanol/DMSO solvent pair (having a DMSO volume ratio of 10%) at 80 C. for 15 hours;

(22) 2) The copolymer film was taken out from the solvent and then was washed in ethanol at room temperature for 5 minutes and then taken out and dried at 30 C. for 2 hours to obtain a nanoporous polymer film.

(23) Implementation Case 5

(24) A method for preparing nanoporous polysulfone-based polymers, whose steps include:

(25) 1) The block copolymer fiber of polyethersulfone and PEG having a PEG volume ratio of 40% was immersed in an ethanol/DMAc solvent pair (having a DMAc volume ratio of 5%) at 30 C. for 24 hours;

(26) 2) The copolymer fiber was taken out from the solvent and then was washed in ethanol at room temperature for 5 minutes and then taken out and dried at 30 C. for 2 hours to obtain a nanoporous polymer fiber.

Contrast Example 1

(27) A method for preparing nanoporous polysulfone-based polymers, whose steps are substantially the same as those of Implementation Case 1, except: the ethanol/acetone solvent pair (having an acetone volume content of 20%) in Implementation Case 1 was changed to pure ethanol but the other operations were unchanged. The treated copolymer remained in a compact initial state with no pores on the surface.

Contrast Example 2

(28) A method for preparing nanoporous polysulfone-based polymers, whose steps are substantially the same as those of Implementation Case 1, except: the ethanol/acetone solvent pair (having an acetone volume content of 20%) in Implementation Case 1 was changed to pure acetone but the other operations were unchanged. The treated copolymer material could not maintain the initial film state, and no pores were formed but spherical micelles were formed in it. Its microstructure is as shown in FIG. 4.