Poly(ether sulfone)s using a rigid dibenzothiophene dioxide heterocycle

Poly(aryl ether)s were prepared by nucleophilic aromatic substitution using conformationally restricted dichloro- and difluorodibenzothiophene dioxide heterocyclic monomers with bisphenol A or bisphenol AF. The heterocyclic monomers were prepared from the bis(4-halophenyl) sulfones in two steps via lithiation followed by copper catalyzed intramolecular coupling and characterized by H-1, C-13, F-19 NMR spectroscopy and GC/MS. Reactivity of the fluorine containing monomer was examined using semi-empirical methods and NMR spectroscopy measurements and found to be potentially more reactive than bis(4-fluorophenyl) sulfone, even with a conformationally locked sulfone as the electron withdrawing group. Successful polymerizations of both the fluorine and chlorine containing monomers with bisphenol A and bisphenol AF nucleophiles were accomplished, providing polymers with number average molecular weights of approximately 45 kg/mol (difluoro monomer) and 10-20 kg/mol (dichloro monomer). The polymers exhibited high T(g)s ranging from 238 to 256 degrees C and displayed good thermal stability with 5% degradation temperatures in air from 453-510 degrees C, depending on molecular weight and bisphenol composition. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3127-3131