Crosslinked, thermally rearranged poly(benzoxazole-co-imide), gas separation membranes comprising the same and preparation method thereof

Patent metadata

Field	Value
Publication number	US-10035109-B2
Application number	US-201415036620-A
Country	US
Kind code	B2
Filing date	Nov 5, 2014
Priority date	Nov 15, 2013
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

The present disclosure relates to a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer membrane 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 gas separation membrane 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 (a membrane for flue gas separation is excluded).
In accordance with the present disclosure, a crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer membrane for 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 gas separation membrane (a membrane for flue gas separation is excluded) 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 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 (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,
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.

2. The crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer according to claim 1 , wherein the copolymer has a d-spacing of 6.67-6.79 Å.

3. The crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer according to claim 1 , wherein the copolymer has a density of 1.38-1.43 g/cm 3 .

4. A method for preparing the crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 1 , 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 by transesterification crosslinking the monoesterified o-hydroxypolyimide copolymer of II); and
IV) thermally rearranging the crosslinked o-hydroxypolyimide copolymer of III).

5. The method for preparing the crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 4 , 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.

6. The method for preparing the crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 4 , 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.

7. The method for preparing the crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 4 , 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, 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.

8. The method for preparing the crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 4 , 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.

9. The method for preparing the crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 4 , wherein the diol in II) is selected from a group consisting of ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol and benzenedimethanol.

10. The method for preparing the crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 4 , wherein the monoesterification in II) is conducted by reacting the copolymer of I) with an excess diol corresponding to 50 or more equivalents of the carboxylic acid groups in the copolymer at 140-160° C. for 18-24 hours in the presence of a p-toluenesulfonic acid catalyst.

11. The method for preparing the crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 4 , wherein the transesterification crosslinking in III) is conducted by heat-treating the copolymer at 200-250° C. for 18-24 hours in vacuo.

12. The method for preparing the crosslinked, thermally rearranged poly(benzoxazole-co-imide) copolymer having a repeat unit represented by Chemical Formula 2 according to claim 4 , wherein the thermal rearrangement in IV) 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.

Assignees

• Iucf Hyu

Inventors

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

Classifications

• C08G73/1067

  Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound · CPC title

• C09D179/08

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

• C08G73/1039

  comprising halogen-containing substituents · CPC title

• B01D71/64 Primary

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

• C08G73/22

  Polybenzoxazoles · CPC title