Ionomer having high oxygen permeability
The present invention aims to provide an ionomer that can exhibit high oxygen permeability, especially under both low- and high-humidified conditions, and high power generation durability. The high oxygen permeable ionomer includes a specific repeating unit A and repeating unit B and has an equivalent weight of 250 to 930 and a glass transition temperature of 100° C. to 130° C.
1. An ionomer, comprising:
a repeating unit A;
a repeating unit B, and
a repeating unit C,
the ionomer having an equivalent weight of 250 to 930 and a glass transition temperature of 100° C. to 130° C.,
the amount of the repeating unit B is 16 to 45 mol %, relative to all the repeating units,
the repeating unit B being represented by the formula (2):
wherein Rp represents a monovalent group having a proton exchange group,
wherein the repeating unit A is at least one repeating unit selected from the group consisting of:
a repeating unit represented by the formula (3):
wherein m 3 represents an integer of 2 to 6; and
a repeating unit represented by the formula (4):
wherein Y 41 represents F or a C1-C3 perfluoroalkyl group; k 4 represents 0 or 1; n 4 represents an integer of 1 to 8; when n 4 represents an integer of 2 to 8, Y 41 in each of respective units —(CF 2 CFY 41 —O) n4 — may be the same as or different from each other; and m 4 represents an integer of 1 to 6,
wherein the repeating unit C that is at least one repeating unit selected from the group consisting of:
a repeating unit represented by the formula (7):
wherein Rf 71 represents F, Cl, or a C1-C9 linear or branched fluoroalkyl group, and
a repeating unit represented by the formula (8):
wherein Y 81 represents H or F; Y 82 represents F or a C1-C9 linear or branched fluoroalkyl group;
and Y 83 represents H, F, Cl, or a C1-C9 linear or branched fluoroalkyl group.
2. The ionomer according to claim 1 ,
wherein the repeating unit B is represented by the formula (5):
wherein Y 51 represents F, Cl, or a C1-C3 perfluoroalkyl group; k 5 represents an integer of 0 to 2; n 5 represents an integer of 0 to 8; when n5 represents an integer of 2 to 8, Y 51 in each of the respective units —(CF 2 CFY 51 —O) n5 — may be the same as or different from each other; Y 52 represents F or Cl; m 5 represents an integer of 2 to 6; Y 52 s the number of which is m 5 may be the same as or different from each other; Z 5 represents H, an alkali metal, an alkaline-earth metal, or NR 51 R 52 R 53 R 54 ; and R 51 , R 52 , R 53 , and R 54 each independently represent a C1-C3 alkyl group or H.
3. The ionomer according to claim 1 ,
wherein the repeating unit B is represented by the formula (6):
wherein Z 5 represents H, an alkali metal, an alkaline-earth metal, or NR 51 R 52 R 53 R 54 ; and R 51 , R 52 , R 53 , and R 54 each independently represent a C1-C3 alkyl group or H.
4. The ionomer according to claim 1 ,
wherein the ionomer contains 5 to 71 mol % of the repeating unit A relative to all the repeating units.
5. An emulsion comprising the ionomer according to claim 1 , and water.
6. An ionomer solution comprising the ionomer according to claim 1 , and water.
7. An electrode catalyst layer comprising the ionomer according to claim 1 .
8. A membrane electrode assembly comprising the electrode catalyst layer according to claim 7 .
9. A fuel cell comprising the membrane electrode assembly according to claim 8 .