Abstract: PES sulphonated with concentrated sulfuric acid and chlorosulfonic acid has been investigated. PEScan not be sulphonated at ambient temperature, but under heating condition it can be sulphonated by concentrated sulfuric acid. The sulphonation degree and degradation of polymer increase with the increase of the temperature and the time. PEScan also be sulphonated by chlorosulfonic acid at ambient temperature. There was a period of time at the beginning of the reaction during which PESis hardly sulphonated if concentrated sulfuric acid was used as solvent. And then, velocity of sulphonation increases obviously. When dichloromethane was used as solvent, the similar results did not exist. Moreover velocity of sulphonation does not change obviously. Structure and properties of sulphonated PES were characterized by means of FTIRand ¹H NMR.

Key words: Polyethersulphone, Sulphonation, S-PES