A fluorinated ion exchange polymer is prepared by grafting a monomer onto
a base polymer, wherein the grafting monomer is selected from the group
consisting of structure 1a, 1b and mixture thereof; ##STR00001## wherein
Y is selected from the group consisting of --R.sub.FSO.sub.2F,
--R.sub.FSO.sub.3M, --R.sub.SO.sub.2NH.sub.2 and
--R.sub.FSO.sub.2N(M)SO.sub.2R.sup.2.sub.F, where in M is hydrogen, an
alkali cation or ammonium; and R.sub.F and R.sup.2.sub.F are
perfluorinated or partially fluorinated, and may optionally include ether
oxygens; and n is between 1 and 2 for 1a, or n is between 1 and 3 for 1b.
These ion exchange polymers are useful is preparing catalyst coated
membranes and membrane electrode assemblies for fuel cells.