Polymeric molecular sieve membranes for gas separation

Patent metadata

Field	Value
Publication number	US-9731249-B2
Application number	US-201514667968-A
Country	US
Kind code	B2
Filing date	Mar 25, 2015
Priority date	Apr 15, 2014
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A porous polymer membrane useful in gas separation, the porous polymer membrane comprising a polymeric structure having crosslinked aromatic groups and a hierarchical porosity in which micropores having a pore size less than 2 nm are present at least in an outer layer of the porous polymer membrane, and macropores having a pore size of over 50 nm are present at least in an inner layer of the porous polymer membrane. Also described are methods for producing the porous polymer membrane in which a non-porous polymer membrane containing aromatic rings is subjected to a Friedel-Crafts crosslinking reaction in which a crosslinking molecule crosslinks the aromatic rings in the presence of a Friedel-Crafts catalyst and organic solvent under sufficiently elevated temperature, as well as methods for using the porous polymer membranes for gas or liquid separation, filtration, or purification.

First claim

What is claimed is:

1. A porous polymer membrane useful in gas separation, the porous polymer membrane comprising a polymeric structure having crosslinked aromatic groups and a hierarchical porosity in which micropores having a pore size less than 2 nm are present at least in an outer layer of the porous polymer membrane, and macropores having a pore size of over 50 nm are present at least in an inner layer of the porous polymer membrane.

2. The porous polymer membrane of claim 1 , wherein said polymeric structure is a polystyrene-containing structure.

3. The porous polymer membrane of claim 1 , wherein the porous polymer membrane has a thickness of at least 50 microns and up to 150 microns.

4. The porous polymer membrane of claim 1 , wherein the porous polymer membrane has a thickness of at least 80 microns and up to 120 microns.

5. The porous polymer membrane of claim 1 , wherein said micropores have a pore size of up to 1 nm.

6. The porous polymer membrane of claim 1 , wherein said macropores have a pore size of at least 100 nm.

7. The porous polymer membrane of claim 1 , wherein said macropores have a pore size of at least 200 nm.

8. The porous polymer membrane of claim 1 , wherein said macropores have a pore size of at least 500 nm.

9. The porous polymer membrane of claim 1 , wherein said macropores have a pore size of at least 1 micron.

10. The porous polymer membrane of claim 1 , wherein said hierarchical porosity further comprises mesopores having a pore size of at least 2 nm and up to 50 nm.

11. The porous polymer membrane of claim 10 , wherein said mesopores are present at least in a surface layer of the porous polymer membrane.

12. The porous polymer membrane of claim 1 , wherein a pore volume due to micropores is greater than the combined pore volume due to macropores and mesopores.

13. A method for fabricating a porous polymer membrane having a hierarchical porosity, the method comprising subjecting a non-porous polymer membrane containing aromatic rings to a Friedel-Crafts crosslinking reaction in which a crosslinking molecule crosslinks said aromatic rings in the presence of a Friedel-Crafts catalyst and organic solvent under sufficiently elevated temperature to provide said porous polymer membrane having a hierarchical porosity, wherein said hierarchical porosity comprises micropores having a pore size less than 2 nm present at least in an outer layer of the porous polymer membrane, and macropores having a pore size of over 50 nm present at least in an inner layer of the porous polymer membrane.

14. The method of claim 13 , wherein said elevated temperature is within a range of 50° C. to 150° C.

15. The method of claim 13 , wherein said elevated temperature is within a range of 60° C. to 120° C.

16. The method of claim 13 , wherein said non-porous polymer has a polystyrene-containing composition.

17. The method of claim 13 , wherein the porous polymer membrane has a thickness of at least 50 microns and up to 150 microns.

18. The method of claim 13 , wherein the porous polymer membrane has a thickness of at least 80 microns and up to 120 microns.

19. The method of claim 13 , wherein said micropores have a pore size of up to 1 nm.

20. The method of claim 13 , wherein said macropores have a pore size of at least 100 nm.

21. The method of claim 13 , wherein said macropores have a pore size of at least 200 nm.

22. The method of claim 13 , wherein said macropores have a pore size of at least 500 nm.

23. The method of claim 13 , wherein said macropores have a pore size of at least 1 micron.

24. The method of claim 13 , wherein said hierarchical porosity further comprises mesopores having a pore size of at least 2 nm and up to 50 nm.

25. The method of claim 24 , wherein said mesopores are present at least in a surface layer of the porous polymer membrane.

26. The method of claim 13 , wherein a pore volume due to micropores is greater than the combined pore volume due to macropores and mesopores.

Assignees

• Ut Battelle Llc

Inventors

• Dai Sheng
• Qiao Zhenan
• Chai Songhai

Classifications

• B01D2325/022

  Asymmetric membranes · CPC title

• B01D2323/30

  Cross-linking · CPC title

• B01D71/28

  Polymers of vinyl aromatic compounds · CPC title

• B01D53/228

  characterised by specific membranes · CPC title

• B01D67/0006

  by chemical reactions (in-situ polymerisation, polycondensation, cross-linking or reaction for manufacturing composite membranes B01D69/125) · CPC title