Abstract
Summary: Radical‐initiated solution copolymerization of N‐vinylimidazole (VIM) and acrylonitrile (AN) was carried out with 2,2^′^‐azobisisobutyronitrile (AIBN) as an initiator in benzene at 70 °C in nitrogen atmosphere. The structure and composition of synthesized copolymers for a wide range of monomer feeds were determined by FTIR, ^1^H and ^13^C NMR spectroscopy with the aid of recorded analytical absorption bands for VIM (667 cm^−1^, CN of imidazole ring) and AN (2 242 cm^−1^, CN group), as well as by using the areas of proton and carbon atom signals from corresponding functional groups of monomer units. Monomer reactivity ratios for VIM (M~1~)‐AN (M~2~) pair were determined by nonlinear regression (NLR), Kelen–Tüdös (KT) and Fineman–Ross (FR) methods. They were found to be r~1~ = 0.24 and r~2~ = 0.15 for the NLR method, r~1~ = 0.22 and r~2~ = 0.094 for the KT method, and r~1~ = 0.24 and r~2~ = 0.12 for the FR method, respectively. The relatively high activity observed of VIM growing macroradical and the results of FTIR and ^1^H NMR structural analysis of copolymers suggest the formation of complexed linkages between monomers and growing radicals in chain propagation reactions. Similar complexation between monomer–comonomer units in the structure of formed macromolecules showed an increase in isotactic triad fractions in the copolymer.
Complex formation between the imidazole ring and nitrile group in both the monomer mixture and chain growing reactions.
imageComplex formation between the imidazole ring and nitrile group in both the monomer mixture and chain growing reactions.