The preparation of poly(2,6-dimethyl-1,4-phenylene oxide) ionomers and their physical properties

Poly(2,6-dimethyl-1,4-phenylene oxide)(PPO) was sulfonated to varying degrees using chlorosulfonic acid as a sulfonating agent. Sulfonated PPO(SPPO) ionomers with low sulfonation degree were characterized by using FTIR, C-13 NMR and acid-base titration. In addition, physical properties such as solubility, thermal properties and mechanical properties were studied. SPPO ionomers become soluble in polar solvent with the increase of sulfonation degree. The glass transition temperature (T-g) increases linearly with sulfonation degree. Elongation of SPPO ionomers were highly enhanced with incorporation of ionic portion. A new transition at lower temperature, which might be due to ionic domain, was also monitored by dynamic mechanical analysis.