POLY(P-PHENYLENE SULFONE)

The title polymer has been synthesized in moderate molecular weight by the self-condensation of sodium 4-halobenzenesulfinate at 175-degrees-C in dimethylsulfoxide. The use of a small amount of 4-fluorophenyl sulfone served to greatly increase the yield of polymer, presumably by acting as an initiator for a chain-type polymerization. The title polymer is highly crystalline (>85%) and poorly soluble in all solvents attempted. The number-average degree of polymerization was estimated to be 10-16 by elemental analysis. No thermal transitions below 500-degrees-C were detected by DSC. The polymer exhibited extremely high and unusual thermal stability when studied by TGA; the onset of significant mass loss occurred at 517-degrees-C in nitrogen and at 555-degrees-C in air. The polymer was characterized by ER and solid-state C-13 NMR spectroscopy and by X-ray diffraction. Analogous model compounds for the trimer and tetramer were prepared and used to confirm the structure of the polymer.