K. B. Wiles, F. Wang and J. E. McGrath
Direct aromatic nucleophilic substitution polycondensations of disodium 3,3′-disulfonate-4,4′-difluorodiphenylsulfone (SDFDPS), 4,4′-difluorodiphenylsulfone (DFDPS) (or their chlorinated analogs, SDCDPS, DCDPS), and 4,4′-thiobisbenzenthiol (TBBT) in the presence of potassium carbonate were investigated. High molecular weight disulfonated poly-(aryelene thioether sulfone) (PATS) copolymers were easily obtained using the SDFDPS monomers, but in general, slower rates and lower molecular weights were obtained using the analogous chlorinated monomers. The degrees of disulfonation (20–50%) were controlled by varying the ratio of disulfonated to unsulfonated comonomers. Proton NMR, infrared spectroscopy, and ion exchange capacity experiments successfully characterized the copolymer structure. Morphological studies using AFM phase imaging coupled with water uptake studies indicated an increase in connectivity of ionic domains from the low disulfonated copolymers to levels of full connectivity for the 40 mol % copolymer.