CHEMICAL MODIFICATION OF POLYSULFONES .2. AN EFFICIENT METHOD FOR INTRODUCING PRIMARY AMINE GROUPS ONTO THE AROMATIC CHAIN

Three modification approaches to aminated polysulfones mere investigated: replacement of aromatic bromine with nucleophilic NH2; amination by electrophilic NH2; and amination of lithiated polysulfones via azides and other electrophilic NH2 synthons. The former two approaches resulted in low levels of amination, or in polymer degradation. For the latter approach using lithiated polysulfones, we report an efficient alternative to the nitration-reduction methodology for introducing amine groups onto polysulfones and poly(aryl sulfones). Polysulfones activated either on the ortho sulfone sites or on the ortho ether sites by direct lithiation or bromination-lithiation, were converted to azides by treatment with tosyl azide, and then reduced to amine derivatives with sodium borohydride. This could be accomplished either by a two-step procedure whereby the azide was isolated, or by a ''one-pot'' modification. Near-quantitative conversions and high levels of functionalization were achieved for the overall process. Polymers having an amine degree of substitution (DS) of 1.0, 2.0, and 2.75 are reported. Structures were confirmed by MMR and IR spectroscopy. GPC, TGA, and T-g data are also reported. A nonquantitative reaction of diphenylphosphoryl azide as well as 4-acetamidobenzenesuIfonyl azide with lithiated polysulfones also gave aminated derivatives.