Polymers and methods for their manufacture
Embodiments of the invention relate to a novel class of polymers with superior mechanical properties and chemical stability, as compared to known polymers. These polymers are particularly well suited for use in anion exchange membranes (AEMs), including those employed in fuel cells. Novel methods for the manufacture of these polymers are also described.
1. A method of forming a polyarylene, the method comprising: reacting an aromatic compound and a trifluoroalkyl ketone in the presence of a strong acid to form a haloalkylated precursor polymer; and reacting the haloalkylated precursor polymer with a quaternary ammonium group to form a polyarylene having a main chain free of ether linkages.
2. The method of claim 1 , wherein the trifluoroalkyl ketone includes at least one trifluoroalkyl ketone selected from a group consisting of: 7-bromo- l, l, l- trifluoroheptan-2-one and methyl trifluoromethyl ketone.
3. The method of claim 1 , wherein the aromatic compound is selected from a group consisting of:
4. The method of claim 3 , wherein the aromatic compound is
5. The method of claim 1 , wherein the aromatic compound is selected from a group consisting of:
wherein each R 1 and R 2 is, independently, R′, and each R′ is, independently,
and wherein n is from 1 to 20.
6. A polymer of formula I prepared according to the method of claim 1
wherein Ar is an aromatic compound, r is from 100 to 1,000,000, and R 2 comprises a quaternary ammonium group.
7. The polymer of claim 6 , wherein Ar is
8. The polymer of claim 7 having formula IA
wherein x+y=1.
9. The polymer of claim 8 , wherein x is 1 and y is 0, or x is 0.65 and y is 0.35, or x is 0.44 and y is 0.56.
10. The polymer of claim 6 , wherein R 2 comprises
R is an alkyl group, and n is from 1 to 20.
11. A polymer according to formula I
wherein Ar is an aromatic compound, r is from 100 to 1,000,000, and R 2 comprises a quaternary ammonium group.
12. The polymer of claim 11 , wherein the aromatic compound is selected from a group consisting of:
13. The polymer of claim 11 , wherein R 2 comprises
R is an alkyl group, and n is from 1 to 20.
14. The polymer of claim 11 , prepared from a bromoalkylated precursor polymer of formula II according to the reaction:
wherein R 1 is
R is an alkyl group, and n is from 1 to 20.
15. The polymer of claim 14 , wherein the bromoalkylated precursor polymer of formula II is prepared according to the reaction:
16. The polymer of claim 15 , wherein the strong acid is trifluoromethanesulfonic acid.
17. The polymer of claim 11 having formula IA
wherein x+y=1.
18. The polymer of claim 17 , wherein x is 1 and y is 0, or x is 0.65 and y is 0.35, or x is 0.44 and y is 0.56.