Poly Subject index

In concentrated sulfuric acid, aromatic polyisocyanides are subject to sulfona-tion. Poly(isopropyl isocyanide) is dissolved in 97%H2S04, and is reprecipitated by the addition of water. Infrared spectra show that some structural change, e.g. hydrolysis, has taken place (26). Poly(sec-butyl isocyanide) is dissolved by the acidic hexafluoroisopropanol with some attendant browning of the solution (7). In spite of the theoretical complexities of polyelectrolytic character introduced into the solution characterization of polyisocyanides in strongly acidic media, such media at least allow viscometric indexing of the various samples of the otherwise insoluble polyisocyanides. 

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