| abstract |
A method of making a copolymer is disclosed. The method includes copolymerizing components including tetrafluoroethylene and a compound represented by formula CF 2 =CF-O-(CF 2 ) a -SO 2 X, wherein "a" is a number from 1 to 4, and X is -NZH, -NZ-SO 2 -(CF 2 ) 1-6 -SO 2 X', or -OZ, wherein Z is independently a hydrogen, an alkali metal cation, or a quaternary ammonium cation, and wherein X' is independently -NZH or -OZ. The components include at least 60 mole % of tetrafluoroethylene based on the total amount of components. A copolymer prepared by the method is also provided. A method of making a membrane using the copolymer is also provided. The present disclosure also provides a polymer electrolyte membrane that includes a copolymer made by the method and a membrane electrode assembly that includes such a polymer electrolyte membrane. |