The sulphonation of polyethersulphone(PES) with oleums gave sulphonated polyethersulphone(SPES) with high sulphonation degree and solubility in water. Results show that the acid strengths of SPES are in 8.2≤-H 0≤11.9 and the catalytic activity and selectivety of SPES are proportional to the sulphonation degree of SPES. The SPES is deactivated rather slowly under experimental conditions.
