Copolymers with cationic, nitrogen-containing groups and anion exchange membranes made therefrom

1. A crosslinkable copolymer comprising:

a) first monomeric units of Formula (I)

wherein

R 1 is an alkyl;

R 2 is an alkyl;

R 3 is an alkylene;

R 4 is hydrogen or methyl;

X is oxy or —NR— where R is hydrogen or alkyl; and

b) second monomeric units of Formula (II)

wherein

R 5 is a cationic, nitrogen-containing group free of a polymerizable group; and

c) third monomeric units of Formula (III-1), Formula (III-2), or a mixture thereof

wherein

R 6 is halo, hydroxy, or alkoxy; and

wherein any cationic group in the copolymer has a corresponding anionic group and wherein each asterisk (*) is the point of attachment to another group or monomeric unit in the copolymer.

2. The crosslinkable copolymer of claim 1 , wherein R 5 of the second monomeric units is a cationic, nitrogen-containing heterocyclic group.

3. The crosslinkable copolymer of claim 2 , wherein the cationic, nitrogen-containing heterocyclic group is a) imidazolium substituted with one or more alkyl groups, b) pyridinium, or c) pyridinium substituted with one or more alkyl groups.

4. The crosslinkable copolymer of claim 1 , wherein 20 to 50 mole percent of the monomeric units in the crosslinkable copolymer are cationic monomeric units of Formula (I) and Formula (II).

5. The crosslinkable copolymer of claim 4 , wherein 1 to 95 percent of the cationic monomeric units are of Formula (I).

6. The crosslinkable copolymer of claim 4 , wherein 5 to 20 percent of the cationic monomeric units are of Formula (I).

7. The crosslinkable copolymer of claim 1 , wherein the copolymer comprises at least 50 mole percent third monomeric units of Formula (III-1), Formula (III-2), or mixtures thereof.

8. The crosslinkable copolymer of claim 1 , wherein the copolymer comprises 50 to 80 mole percent third monomeric units of Formula (III-1), Formula (III-2), or mixtures thereof.

9. The crosslinkable copolymer of claim 8 , wherein 55 to 70 percent of the third monomeric units are of Formula (III-1) and 30 to 45 percent of the third monomeric units are of Formula (III-2).

10. The crosslinkable copolymer of claim 1 , wherein the crosslinkable copolymer comprises 1 to 10 mole percent monomeric units of Formula (I), 10 to 49 mole percent monomeric units of Formula (II), 50 to 80 mole percent monomeric units of Formula (III-1), and 0 to 20 mole percent monomeric units of Formula (III-2) based on total moles of monomeric units in the crosslinkable copolymer.

11. A crosslinked copolymer comprising a crosslinked reaction product of the crosslinkable copolymer of claim 1 .

12. An anion exchange membrane comprising the crosslinked copolymer of claim 11 .

13. The anion exchange membrane of claim 12 , further comprising a catalyst layer adjacent to a first major surface and/or a second major surface of the anion exchange membrane.

14. An electrochemical device comprising:

an anode;

a cathode; and

a membrane positioned between the anode and cathode, wherein the membrane is of claim 12 .

15. A method of making a crosslinked copolymer, the method comprising:

providing a precursor copolymer comprising

monomeric units derived from styrene; and

monomeric units derived from vinylbenzyl halide;

reacting the precursor copolymer with a base composition to form a crosslinkable copolymer, wherein the base composition comprises

a) a first nitrogen-containing based of Formula (IV)

R 1 R 2 N—R 3 —X—CO—CR 4 ═CH 2   (IV)

where R 1 and R 2 are each independently an alkyl, R 3 is an alkylene, X is oxy or —NR—

where R is hydrogen or alkyl, and R 4 is hydrogen or alkyl; and

b) a second nitrogen-containing base, wherein the second nitrogen-containing base is free of a polymerizable group; and

mixing the crosslinkable copolymer with a photoinitiator to prepare a crosslinkable composition; and

exposing the crosslinkable composition to ultraviolet radiation to form the crosslinked copolymer.