Copolymerization Reactivity and Behavior of N-Vinylimidazole with α,β-Disubstituted Monomers

The copolymerization of N-vinylimidazole (NVIm) with 11 different comonomers was investigated. The monomer reactivity ratios of each copolymerization system were determined by the Kelen-Tüdös method illustrated in the copolymerization diagrams. Those values were more reliable than those determined by the Fineman-Ross method. Alfrey-Price's Q and e values for NVIm were given as 0.128 ± 0.003 and −0.879 ± 0.038, respectively, from NVIm-styrene and NVIm-methyl methacrylate systems. Those copolymerization parameters suggest that the reactivity of NVIm for the growing radical of the comonomer was proportional to the Hammett's para-substituent constant for substituent of the comonomer and that alkyl fumarates were more reactive than alkyl maleates in copolymerization with NVIm. Although the charge transfer (CT) interaction between NVIm and comonomers with e values greater than 1.8 was observed by the spectroscopic “continuous variation method,” the CT alternating copolymerization mechanism cannot be utilized in this study, as explained in the discussion of the run number, as an index of the alternating tendency, the copolymer composition, and the rate of copolymerization.