Copolymers of N-cyclohexylacrylamide and n-butyl acrylate: synthesis, characterization, monomer reactivity ratios and mean sequence length

Abstract

Copolymerization of N-cyclohexylacrylamide (NCHA) and n-butyl acrylate (BA) was carried out in dimethylformamide at 551C using azobisisobutyronitrile as a free radical initiator. The copolymers were characterized by 1 H-NMR spectroscopy and the copolymer compositions were determined by 1 H-NMR analysis. The reactivity ratios of the monomers were determined by both linear and non-linear methods. The reactivity ratios of monomers determined using linear methods like Fineman-Ross (r1 = 0.37 and r2 = 1.77 ), Kelen-Tudos (r1 = 0.38 and r2 = 1.77), ext. Kelen-Tudos (r1 = 0.37 and r2 = 1.75) Yezrieler-Brokhina-Roskin (r1 = 0.37 and r2 = 1.77) and non-linear methods like Tidwell-Mortimer (r1 = 0.37 and r2 = 1.76), ProCop (r1 = 0.36 and r2 = 1.82). The Q and e values for NCHA are 0.67 and 0.68 respectively. Mean sequence lengths of copolymers are estimated from r1 and r2 values. It shows that the BA units increases in a linear fashion in the polymer chain as the concentration of BA increases in the monomer feed.