High molecular weight poly(phenylene sulfide ether) (PPSE) was successfully synthesized by reaction of 4,4'-dihydroxy diphenyl sulfide with 4'-dichloro diphenyl Sulfide in N-methyl-2-pyrrolidone (NMP). The influence of polymerization conditions on the intrinsic viscosity and yield of PPSE was investigated and the optimized reaction condition was concluded. Reactions at about 180 degrees C for 6 h alone with sodium benzoate as an additive and monomer concentration of 0.588 mol/L NMP were found to produce the highest intrinsic viscosity (0.55 dL/g). Longer reaction time and/or higher temperature reduced the intrinsic viscosity and yield of the resulting product, probably due to side reactions, such as reductive dehalogenation and chemical degradation. X-ray diffraction indicated that the polymer possessed of orthorhombic cell and had a high crystallinity of 65.8%. The high molecular weight PPSE is a crystalline polymer with T-m of 252 degrees C and T-mc of 224 degrees C. The polymer shows good chemical resistance, but is Soluble in organic amide, halo-hydrocarbon and oxohydrocarbon solvent at a temperature over 150 degrees C. (C) 2008 Wiley Periodicals, Inc.