Crosslinked polymeric blended membranes for gas separation

1. A method of making a gas separation membrane comprising:

dissolving a poly(ether-b-amide) (PEBA) copolymer in a solvent to form a polymer solution;

casting the polymer solution into a mold;

evaporating the solvent to form a film;

submerging the film in a crosslinking solution to form a crosslinked film, wherein the crosslinking solution comprises a diisocyanate polyether according to formula (I):

where

R 6 is independently an alkyl or —H;

x is from 1 to 200; and

R 1 , R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 , and R 11 is independently —C═N═O, alkyl or —H, provided that at least one and not more than two of R 1 , R 2 , R 3 , R 4 and R 5 is —C═N═O and at least one and not more than two of R 7 , R 8 , R 9 , R 10 , and R 11 is independently —C═N═O; and

drying the film to form the gas separation membrane.

2. The method of making a gas separation membrane of claim 1 , in which the poly(ether-b-amide) copolymer comprises a 25 to 80% by weight polyether segment and a 75 to 20% by weight polyamide segment.

3. The method of making a gas separation membrane of claim 1 , in which R 6 is methyl or —H.

4. The method of making a gas separation membrane of claim 1 , in which R 4 and R 8 are —C═N═O; and R 3 and R 9 are methyl.

5. The method of making a gas separation membrane of claim 1 , in which the polymer solution comprises 1 to 99 weight percent of poly(ether-b-amide) copolymer.

6. The method of making a gas separation membrane of claim 1 , in which the crosslinking solution comprises 2 to 40 weight percent of the crosslinker according to formula (I).

7. The method of making a gas separation membrane of claim 1 , in which the crosslinking solution had a temperature of from 35 to 85° C.

8. The method of making a gas separation membrane of claim 1 , in which the gas separation membrane was dried at a temperature of from 35 to 90° C.

9. A method of gas separation, the method comprising:

flowing a gas stream through a gas separation membrane, the gas separation membrane comprising a polyether block amide (PEBA) crosslinked by a diisocyanate polyether according to formula (I):

where

each R 6 is independently an alkyl or —H;

x is from 1 to 200; and

R 1 , R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 , and R 11 is independently —C═N═O, alkyl or —H, provided that at least one and not more than two of R 1 , R 2 , R 3 , R 4 and R 5 is —C═N═O and at least one and not more than two of R 7 , R 8 , R 9 , R 10 , and R 11 is independently —C═N═O; and

separating the gases via the gas separation membrane.

10. A gas separation membrane comprising cross-linked poly(ether-b-amide) copolymer, in which the poly(ether-b-amide) copolymer comprise urethane crosslinks which is the reaction product of poly(ether-b-amide) copolymer and diisocyanate polyether according to formula (I):

where

each R 6 is independently an alkyl or —H;

x is from 1 to 200; and

R 1 , R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 , and R 11 is independently —C═N═O, alkyl or —H, provided that at least one and not more than two of R 1 , R 2 , R 3 , R 4 and R 5 is —C═N═O and at least one and not more than two of R 7 , R 8 , R 9 , R 10 , and R 11 is independently —C═N═O.

11. The gas separation membrane according to claim 10 , in which the gas separation membrane further comprises a thickness of from 30 to 70 micrometers (μm).

12. The gas separation membrane according to claim 10 , in which R 6 is methyl or —H.

13. The gas separation membrane according to claim 10 , in which R 4 and R 8 are —C═N═O; and R 3 and R 9 are methyl.

14. The gas separation membrane according to claim 10 , in which the gas separation membrane further comprises 1 to 99% by weight of poly(ether-b-amide) copolymer.

15. The gas separation membrane according to claim 10 , in which the gas separation membrane further comprises 2 to 40% by weight of the diisocyanate polyether according to formula (I).

16. A method of making a gas separation membrane comprising:

dissolving a poly(ether-b-amide) (PEBA) copolymer and an amount of a diisocyanate polyether according to formula (I) in a solvent to form a polymer crosslinking solution:

where

R 6 is independently an alkyl or —H;

x is from 1 to 200; and

R 1 , R 2 , R 3 , R 4 , R 5 , R 7 , R 8 , R 9 , R 10 , and R 11 is independently —C═N═O, alkyl or —H, provided that at least one and not more than two of R 1 , R 2 , R 3 , R 4 and R 5 is —C═N═O and at least one and not more than two of R 7 , R 8 , R 9 , R 10 , and R 11 is independently —C═N═O; and

casting the polymer crosslinking solution into a mold;

evaporating the solvent to form a crosslinked film;

drying the film to form the gas separation membrane.

17. The method of making a gas separation membrane of claim 16 , in which the poly(ether-b-amide) copolymer comprises a 25 to 80% by weight polyether segment and a 75 to 20% by weight polyamide segment.

18. The method of making a gas separation membrane of claim 16 , in which R 6 is methyl or —H.

19. The method of making a gas separation membrane of claim 16 , in which R 4 and R 8 are —C═N═O; and R 3 and R 9 are methyl.

20. The method of making a gas separation membrane of claim 16 , in which the polymer crosslinking solution comprises 1 to 99 weight percent of poly(ether-b-amide) copolymer.

21. The method of making a gas separation membrane of claim 16 , in which the polymer crosslinking solution comprises 2 to 40 weight percent of the diisocyanate polyether according to formula (I).

22. The method of making a gas separation membrane of claim 16 , in which the polymer crosslinking solution was heated at a temperature of from 35 to 85° C.

23. The method of making a gas separation membrane of claim 16 which the gas separation membrane was dried at a temperature of from 35 to 50° C.