Nuclear magnetic resonance studies of N‐vinylcarbazole/methyl methacrylate copolymers

Abstract

Copolymers of N-vinylcarbazole and methyl methacrylate of different compositions were prepared by solution polymerization with azobisisobutyronitrile as an initiator, and their compositions were determined from quantitative 13 C{ 1 H}-NMR spectroscopy. The reactivity ratios for the comonomers were calculated with the KelenTudos and nonlinear error-in-variable methods. The complete spectral assignment of the overlapping 1 H and 13 C{ 1 H} spectra of the copolymers was made with the help of distortionless enhancement by polarization transfer, two-dimensional heteronuclear single-quantum correlation, and total correlation spectroscopy.

Photophysical studies of copolymers of N‐vinylcarbazole

“…The compositions of copolymers were determined from quantitative 13 C{ 1 H} NMR spectroscopy 27–30. The mole fraction of N ‐vinylcarbazole (V) in feed and in the copolymer and that of VV dyad and the molecular weight averages of these copolymers are shown in Table I.…”

“…We had reported the NMR studies of these copolymers in our earlier papers 27–30. The reactivity ratios of these copolymers were determined by Kelen–Tudos method and nonlinear error in variable method, which are based on the terminal model of copolymerization.…”

“…By comparing the experimental out‐feed values and those calculated by these reactivity ratios, it is confirmed that these copolymers follow First Order Markov model. The sequencing and characterization of these copolymers are well‐described using one‐ and two‐dimensional NMR spectroscopy in our earlier publications on these copolymers 27–30…”

One- and two-dimensional NMR studies of methyl acrylate/vinyl acetate/N-vinyl carbazole terpolymers

“…This is due to the fact that 13 C{ 1 H} NMR chemical shifts are extremely sensitive to monomer and stereosequence effects. Various coworkers [18][19][20][21][22] have investigated the microstructure of N-vinyl carbazole based copolymers with different monomers. The stereosequence of different triads in various carbazole copolymers and terpolymers have earlier been reported using various 2D NMR techniques [23][24][25][26][27].…”