Poly(arylene ether diketone)s were prepared by the aromatic nucleophilicdisplacement reaction of 4

4'-difluorobenzil with different bisphenols in the presence of an-hydrous potassium carbonate in diphenylsulfone at elevated temperature. The polymersobtained had inherent viscosity of 0.51 ～ 0.63 dL/g

and exhibited glass transition temper-ature ranging from 136 ～217℃ mainly depending on the bisphenols used in the polymersynthesis. Thermogravimetry of these polymers showed excellent thermal stability

indi-cating that 10% weight losses of the polymers were observed in the range above 428℃ and 438℃ in air and nitrogen

respectively.The mechanical properties of these polymers were also described and the permeability of five polymers for H2

O2and N2 was determined at 30℃.