Three amorphous aromatic polyether sulfone(ketone)s with different structures underwent a cyclo-depolymerization reaction using CsF as the catalyst in dipolar aprotic solvents such as DMAc and DMF to afford corresponding cyclic oligomer products.The results were confirmed by GPC, HPLC and MALDI-TOF-MS.The yields of phenolphthalein polyether sulfone (PES-C) and phenolphthalein polyether ketone (PEK-C) cyclics reach as high as 86.3% and 87.9% respectively.Relative factors that influence the yields of cyclics were discussed.High molecular weight linear products were regenerated after the ring-opening polymerization of the cyclo-products using potassium phenoxide as initiator.

Key words: amorphous polyether sulfone(ketone), cyclo-depolymerization, cyclic oligomer, cesium fluoride