Radical Homopolymerization of a Trisubstituted Alkene: 1-CyclobutenecarboxylicAcid and It's Polymer

摘要

Unexpected formation of an insoluble polymer during purification of 1-cyclobutenecarboxylic acid led to solid state 13C NMR characterization which seemed to indicate vinyl polymerization was occurring. Deliberate attempts to induce radical polymerization involved photoinitiation with 2,2-dimethyoxy-2-phenylacetophenone (Irgacure 651) in N,N-dimethylformamide (DMF) or tetrahydrofuran (THF) to give a product that was soluble in dimethylsulfoxide (DMSO) and very soluble in aqueous base. Spectral characterization with 13C NMR in solution (DMSO-d(6)) 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. Intrinsic viscosities of the potassium salt of the polymer in pure water and in 1 N aqueous NaCI were ca 2.25 grams per deciLiters and 0.27 g/dL, respectively, consistent with a polyelectrolyte effect in water and a reasonable molecular weight. Keywords: Homopolymerization, Trisubstituted alkene, 1-Cyclobutenecarboxylic acid, Polymers, Composite materials. (JG)