Membranes for flue gas separation comprising crosslinked, thermally rearranged poly(benzoxazole-co-imide) and preparation method thereof

Patent metadata

Field	Value
Publication number	US-10040034-B2
Application number	US-201415036727-A
Country	US
Kind code	B2
Filing date	Nov 5, 2014
Priority date	Nov 15, 2013
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

The present disclosure relates to a membrane for flue gas separation containing a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer prepared simply by heat-treating a membrane prepared from an o-hydroxypolyimide copolymer having carboxylic acid groups such that thermal crosslinking and thermal rearrangement occur simultaneously or a membrane for flue gas separation containing a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a benzoxazole group content of less than 80% in the polymer chain, prepared from transesterification crosslinking of an o-hydroxypolyimide copolymer having carboxylic acid groups and a diol-based compound followed by thermal rearrangement, and a method for preparing the same.
In accordance with the present disclosure, a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer membrane for flue gas separation can be prepared simply through heat treatment without requiring a complicated process such as chemical crosslinking, UV irradiation, etc. for forming a crosslinked structure and a membrane for flue gas separation prepared therefrom exhibits superior permeability and selectivity. Also, the method is applicable to commercial-scale production because the preparation process is simple.

First claim

The invention claimed is:

1. A method for preparing a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer membrane for flue gas separation, comprising:
i) obtaining a polyamic acid solution by reacting an acid dianhydride, an o-hydroxydiamine and 3,5-diaminobenzoic acid, as a comonomer, and synthesizing an o-hydroxypolyimide copolymer having carboxylic acid groups through azeotropic thermal imidization;
ii) preparing a membrane by dissolving the o-hydroxypolyimide copolymer having carboxylic acid groups synthesized in i) in an organic solvent and casting the same; and
iii) heat-treating the membrane obtained in ii).

2. The method for preparing a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer membrane for flue gas separation according to claim 1 , wherein the acid dianhydride in i) is represented by General Formula 1:

wherein Ar is an aromatic ring group selected from a substituted or unsubstituted tetravalent C 6 -C 24 arylene group and a substituted or unsubstituted tetravalent C 4 -C 24 heterocyclic ring group, wherein the aromatic ring group exists on its own, forms a condensed ring with each other, or is linked with each other by a single bond, O, S, CO, SO 2 , Si(CH 3 ) 2 , (CH 2 ) p (1≤p≤10), (CF 2 ) q (1≤q≤10), C(CH 3 ) 2 , C(CF 3 ) 2 or CO—NH.

3. The method for preparing a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer membrane for flue gas separation according to claim 1 , wherein the o-hydroxydiamine in i) is represented by General Formula 2:

wherein Q is a single bond, O, S, CO, SO 2 , Si(CH 3 ) 2 , (CH 2 ) p (1≤p≤10), (CF 2 ) q (1≤q≤10), C(CH 3 ) 2 , C(CF 3 ) 2 , CO—NH, C(CH 3 )(CF 3 ) or a substituted or unsubstituted phenylene group.

4. The method for preparing a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer membrane for flue gas separation according to claim 1 , wherein the azeotropic thermal imidization in i) is conducted by adding toluene or xylene to the polyamic acid solution and stirring the mixture at 180-200° C. for 6-12 hours.

5. The method for preparing a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer membrane for flue gas separation according to claim 1 , wherein the heat treatment in iii) is conducted by raising temperature to 350-450° C. at a rate of 1-20° C/min under high-purity inert gas atmosphere and maintaining the temperature for 0.1-3 hours.

6. A membrane for flue gas separation comprising a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2:

wherein
Ar 1 is an aromatic ring group selected from a substituted or unsubstituted tetravalent C 6 -C 24 arylene group and a substituted or unsubstituted tetravalent C 4 -C 24 heterocyclic ring group, wherein the aromatic ring group exists on its own, forms a condensed ring with each other, or is linked with each other by a single bond, O, S, CO, SO 2 , Si(CH 3 ) 2 , (CH 2 ) p (1≤p≤10), (CF 2 ) q (1≤q≤10), C(CH 3 ) 2 , C(CF 3 ) 2 or CO—NH,
Q is a single bond, O, S, CO, SO 2 , Si(CH 3 ) 2 , (CH 2 ) p (1≤p≤10), (CF 2 ) q (1q≤10), C(CH 3 ) 2 , C(CF 3 ) 2 , CO—NH, C(CH 3 )(CF 3 ) or a substituted or unsubstituted phenylene group,
Ar 2 is an aromatic ring group selected from a substituted or unsubstituted divalent C 6 -C 24 arylene group and a substituted or unsubstituted divalent C 4 -C 24 heterocyclic ring group, wherein the aromatic ring group exists on its own, forms a condensed ring with each other, or is linked with each other by a single bond, O, S, CO, SO 2 , Si(CH 3 ) 2 , (CH 2 ) p (1≤p≤10), (CF 2 ) q (1≤q≤10), C(CH 3 ) 2 , C(CF 3 ) 2 or CO—NH, and
x, y and z are molar fractions in the repeat unit, satisfying x<0.8 and x+y+z=1, except for the case where x, y or z is 0.

7. The membrane for flue gas separation comprising a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer according to claim 6 , wherein the copolymer has a d-spacing of 6.67-6.79 Å.

8. The membrane for flue gas separation comprising a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer according to claim 6 , wherein the copolymer has a density of 1.38-1.43 g/cm 3 .

9. A method for preparing the membrane for flue gas separation comprising a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 6 , comprising:
I) obtaining a polyamic acid solution by reacting an acid dianhydride, an o-hydroxydiamine and an aromatic diamine and 3,5-diaminobenzoic acid, as comonomers, and synthesizing an o-hydroxypolyimide copolymer having carboxylic acid groups through azeotropic thermal imidization;
II) synthesizing a monoesterified o-hydroxypolyimide copolymer by reacting the polyimide copolymer of I) with a diol;
III) synthesizing a crosslinked o-hydroxypolyimide copolymer membrane by casting a polymer solution obtained by dissolving the monoesterified o-hydroxypolyimide copolymer of II) in an organic solvent and transesterification crosslinking the same; and
IV) thermally rearranging the crosslinked o-hydroxypolyimide copolymer membrane of III).

10. The method for preparing the membrane for flue gas separation comprising a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 9 , wherein the acid dianhydride in I) is represented by General Formula 3:

wherein Ar 1 is an aromatic ring group selected from a substituted or unsubstituted tetravalent C 6 -C 24 arylene group and a substituted or unsubstituted tetravalent C 4 -C 24 heterocyclic ring group, wherein the aromatic ring group exists on its own, forms a condensed ring with each other, or is linked with each other by a single bond, O, S, CO, SO 2 , Si(CH 3 ) 2 , (CH 2 ) p (1≤p≤10), (CF 2 ) q (1≤q≤10), C(CH 3 ) 2 , C(CF 3 ) 2 or CO—NH.

11. The method for preparing the membrane for flue gas separation comprising a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 9 , wherein the o-hydroxydiamine in I) is represented by General Formula 2:

wherein Q is a single bond, O, S, CO, SO 2 , Si(CH 3 ) 2 , (CH 2 ) p (1≤p≤10), (CF 2 ) q (1≤q≤10), C(CH 3 ) 2 , C(CF 3 ) 2 , CO—NH, C(CH 3 )(CF 3 ) or a substituted or unsubstituted phenylene group.

12. The method for preparing the membrane for flue gas separation comprising a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 9 , wherein the aromatic diamine in I) is represented by General Formula 4:
H 2 N—Ar 2 —NH 2   <General Formula 4>

wherein Ar 2 is an aromatic ring group selected from a substituted or unsubstituted divalent C 6 -C 24 arylene group and a substituted or unsubstituted divalent C 4 -C 24 heterocyclic ring group, wherein the aromatic ring group exists on its own, foiiiis a condensed ring with each other, or is linked with each other by a single bond, O, S,

Assignees

• Iucf Hyu

Inventors

• Lee Young Moo
• Calle Mariola
• Jo Hye Jin
• Lee Jongmyeong

Classifications

• B01D67/0006

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

• C08J2379/08

  Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors · CPC title

• B01D2323/30

  Cross-linking · CPC title

• C08G73/22

  Polybenzoxazoles · CPC title

• C08J3/247

  Heating methods · CPC title