Radical Homopolymerization of a Trisbustituted Alkene - 1-Cyclobutenecarboxylic Acid and Its Polymer
Polymers and High Performance Materials
Unexpected formation of an insoluble polymer during purification of 1-cyclobutenecarboxylic acid led to solution and solid state C-13 n.m.r. characterization which seemed to indicate vinyl polymerization was occurring. Deliberate attempts to induce radical polymerization by photoinitiation with 2,2-dimethoxy-2-phenylactophenone (Irgacure 651) in N,N-dimethylformamide (DMF) or tetrahydrofuran (THF) gave a product that was soluble in dimethylsulphoxide (DMSO) and very soluble in aqueous base. Spectral characterization with C-13 n.m.r. in solution (DMSO-d6) and CP/MAS confirmed vinyl polymerization and the presence of pendent carboxylic acid groups. Notably absent were peaks due to ester linkages and backbone or pendent unsaturation leading to the conclusion that the polymer contains backbone cyclobutane units. Intrinsic viscosities of the potassium salt of the polymer in pure water and in 1 N aqueous NaCl were c. 2.25 dl g-1 and 0.27 dl g-1 respectively, consistent with a polyelectrolyte effect in water and a reasonable molecular weight.
Casey, P. K.,
Mathias, L. J.
(1991). Radical Homopolymerization of a Trisbustituted Alkene - 1-Cyclobutenecarboxylic Acid and Its Polymer. Polymer Communications, 32(1), 27-29.
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