Synthesis and sulfonation of poly(aryl ethers) containing triphenyl methane and tetraphenyl methane moieties from isocynate-masked bisphenols

Wholly aromatic poly(aryl ethers) containing triphenylmethane and tetraphenylmethane moieties were successfully synthesized by aromatic nucleophilic substituting polycondensation from masked bisphenols and decafluorobiphenyl followed by sulfonation with chlorosulfonic acid. The sulfonation took place only at the para positions on the pendant phenyl rings due to the novel biphenol structures designed. For the synthesized polymers, the sulfonation content can be easily controlled and the water-takeup can be conveniently tailored by changing the amount of sulfonation agent. These sulfonated polymers are soluble in polar organic solvents, such as NMP, dimethylacetamide; dimethyl sulfoxide, dimethylformamide, and ethylene glycol monomethyl ether and can be readily cast into tough and smooth films from solutions. The films exhibited very high water absorption ability and superior mechanical strength. These polymers also showed high glass transition temperatures ranging from 176 to 203 degreesC compared with Nafion. The sulfonated polymers can be potentially used as the proton-exchange membranes for fuel cells.