Microstructure analysis of N-vinyl-2-pyrrolidone/vinyl acetate copolymers by NMR spectroscopy

N-Vinyl-2-pyrrolidone (F) and vinyl acetate (A) copolymers of different compositions were synthesized by free radical bulk polymerization. The copolymer composition of these copolymers was determined using quantitative C-13{H-1} NMR spectra. The reactivity ratios for these comonomers were determined using the Kelen-Tudos (KT) and non-linear least-square error-in-variable (EVM) methods. The reactivity ratios calculated from the KT and EVM methods are r(v)=2.86+/-0.16, r(A)= 13 0.36 +/- 0.09 and r(v)=2.56, r(A)=0.33, respectively. H-1, C-13{H-1} and C-13 heteronuclear shift correlation spectroscopy (HSQC) and H-1-H-1 homonuclear total correlation spectroscopy (TOCSY) were used for the compositional and configurational assignments of VIA copolymers. The C-13 distortionless enhancement by polarization transfer (DEPT) technique was used to resolve the methine, methylene and methyl resonance signals in the VIA copolymers. (C) 2002 Society of Chemical Industry.