Abstract: A series of sulfonated poly (2, 6-dimethyl-1, 4-phenylene oxide) (S-PPO) were prepared.The solution behavior of S-PPO with 20.9 mol% sulfonyl group and its salts in mixedTHF/MeOH was studied.It is shown that the state of ehain aggregation of S-PPO ionomersin solvent was e'osely related to the polymer coneentration and radius of the cation of salts.The relationship between degree of aggregation and ionomer eoneentration was DA = Ke^BC when the eoneentration was higher than 3g/dL.Here K and β were the eonstants relatedto the starting aggregation eoneentration and the rate of ehain aggregation, respeetively.

Key words: sulfonated poly(2,6-dimethyl-1,4-phenylene oxide),ionomer solution, aggregation state