Studies of the Effect of Comonomers on the Microstructure of Polyacrylonitrile in Radical Polymerization Using NMR Spectroscopy

The free radical polymerization method has been employed to synthesize homopolymers of acrylonitrile (AN), its copolymers with methylacrylate (MA) and terpolymers containing itaconic acid (IA) in homogeneous solution (aqueous solution of sodium thiocyanate and dimethylsulfoxide media) and aqueous redox slurry system. 13 C NMR was used to characterize these polymers in terms of steric configurations in order to study the effect of co and ter monomers on microstructure of polyarylonitrile both at low and high conversions. The study showed no significant change in microstructure of polyacrylonitrile on the introduction of MA and IA. Different techniques of polymerization for ACN-MA-IA had no effect on the microstructure of terpolymer. 1 H NMR and IR techniques were used to determine the composition of copolymers and a good agreement was observed between the results from the two techniques. The presence of unsaturated carboxylic acid monomer (IA) was confirmed by 1 H NMR.