Solution polymerization of acrylonitrile with vinyl acids in dimethylformamide

Solution copolymerization of acrylonitrile (AN) with various vinyl acids, i.e., acrylic acid (AA), methacrylic acid (MAA), and itaconic acid (IA), was carried out in DMF at 70 degrees C using alpha,alpha-azobisisobutyronitrile (AIBN) as an initiator with an acidic monomer of 0.012-0.092 mol %. Copolymers were characterized by FTIR, CHN analysis, H-1- and C-13-NMR, and viscometry. The reactivity ratios were calculated using Fineman-Ross and Kelen-Tudos methods. In all three systems, the value of r(1) (AN) is much less than the value of r(2). However, the r(2) (MAA) is higher than r(2) of (AA) and (IA). The reactivity ratios were calculated using Q and e schemes also. The results are in good agreement with experimentally calculated data. The tacticity and sequence length distribution of these copolymers were calculated using C-13-NMR from C=N and CH signals. It was observed that the isotacticity of acrylonitrile-itaconic acid copolymer P(AN-IA) with 8.2 mol % of a comonomer is lower than that of P(AN-MAA) with 10.3 mol % and P(AN-AA) with 7.61 mol %. (C) 1996 John Wiley & Sons.