Characterization of 4-vinylpyridine-styrene copolymer by NMR spectroscopy

4-Vinylpyridine-styrene (V/S) copolymers of different compositions have bee n prepared by free radical bulk polymerization. The copolymer composition h as been calculated from H-1 NMR spectra. The co-monomer reactivity ratios o f V/S copolymer have been calculated from Kelen - Tudos (KT) and non-linear error in variables methods (EVM). The reactivity ratios obtained from KT a nd EVM are r(V) = 0.85, r(S) = 0.67 and r(V) =0.80 +/- 0.20, r(S) = 0.66 +/ - 0.05 respectively. The copolymerization parameters such as conditional pr obabilities, number - average sequence lengths and block character in the c opolymers have been calculated from C-13{H-1} NMR spectra. The observed tri ads concentration as determined from C-13{H-1} NMR spectra are in good agre ement with those calculated from statistical model using terminal model rea ctivity ratios. The complete spectral assignment of these copolymers has be en done with the help of Distortionless Enhancement by Polarization Transfe r (DEPT) and two dimensional heteronuclear single quantum coherence (HSQC) spectra. The various type of H-1 - H-1 couplings in copolymer are assigned with the help of 2D-Total correlated spectroscopy (TOCSY).