Polymer, polymer electrolyte membrane for polymer electrolyte fuel cell, and membrane/electrode assembly
View Patent ↗A polymer electrolyte membrane made of a polymer having a low electrical resistance, high heat resistance and is strong against repeats of swelling and shrinkage. Thus, a membrane/electrode assembly for polymer electrolyte fuel cells having high power generation performance and excellent in durability can be provided. The polymer has repeating units represented by the following formula (U1 ) and repeating units represented by the following formula (U2):
1. A polymer comprising repeating units represented by the following formula (U1) and repeating units represented by the following formula (U2):
wherein Q 1 is a perfluoroalkylene group which may have an etheric oxygen atom, Q 2 is a single bond or a perfluoroalkylene group which may have an etheric oxygen atom, R f1 is a perfluoroalkyl group which may have an etheric oxygen atom, X 1 is an oxygen atom, a nitrogen atom or a carbon atom, a is 0 when X 1 is an oxygen atom, 1 when X 1 is a nitrogen atom, or 2 when X 1 is a carbon atom, Y 1 is a fluorine atom or a monovalent perfluoroorganic group, and s is 0 or 1;
Q 3 is a single bond or a perfluoroalkylene group which may have an etheric oxygen atom, R f2 is a perfluoroalkyl group which may have an etheric oxygen atom, X 2 is an oxygen atom, a nitrogen atom or a carbon atom, b is 0 when X 2 is an oxygen atom, 1 when X 2 is a nitrogen atom, or 2 when X 2 is a carbon atom, Y 2 is a fluorine atom or a monovalent perfluoroorganic group, and t is 0 or 1.
2. The polymer according to claim 1 , which further comprises repeating units based on tetrafluoroethylene.
3. The polymer according to claim 1 , which has an equivalent weight of from 400 to 900 g/equivalent.
4. The polymer according to claim 1 , wherein (repeating units represented by the formula (U2))/(repeating units represented by the formula (U1)+repeating units represented by the formula (U2)) is from 0.2 to 0.7 (molar ratio).
5. The polymer according to claim 2 , which has an equivalent weight of from 400 to 900 g/equivalent.
6. The polymer according to claim 2 , wherein (repeating units represented by the formula (U2))/(repeating units represented by the formula (U1)+repeating units represented by the formula (U2)) is from 0.2 to 0.7 (molar ratio).
7. The polymer according to claim 6 , which has an equivalent weight of from 400 to 900 g/equivalent.