Modified polysulfones. IV. Synthesis and characterization of polymers withsilicon substituents for a comparative study of gas-transport properties

We previously conducted a detailed study Df gas-transport and other propert ies of a series of silicon derivatives of Udel polysulfone (PSf) and Radel polyphenylsulfone; we now report the details of their preparation by the re action of lithiated polymer intermediates with chlorosilylalkylaryl electro philes. Ortho-sulfone-substituted polymers with pendant tri:methylsilyl, di methylphenylsilyl, and diphenylmethylsilyl and other groups were obtained b y direct metalation followed by the reaction of the dilithiated intermediat e with the appropriate silyl electrophile. In addition, the structural regu larity and geometry of the dilithiated site was also exploited to introduce silicon into the main chain by the reaction of dichlorosilyl electrophiles , leading to the formation of a new tricyclic heteroatom ring. Ortho-ether PSf derivatives were obtained from a dibrominated polymer via the lithiatio n of brominated polymer and reaction with a silyl electrophile. The degree of substitution of the silyl groups was 2.0 or less from dilithiated polyme rs and was dependent on the electrophile reactivity and reaction conditions . A detailed structural characterization of the polymers by NMR and IR spec troscopy is reported in addition to glass-transition temperatures and therm al stabilities. (C) 2001 John Wiley & Sons, Inc.