One- and two-dimensional nuclear magnetic resonance studies on the compositional sequence and the microstructure of acrylonitrile-pentyl methacrylate copolymers

Abstract

The chemical microstructure of acrylonitrile–pentyl methacrylate (A–P) copolymers prepared by photopolymerization using uranyl ion as the photo sensitizer is analyzed by 13C{1H} nuclear magnetic resonance spectroscopy. The composition of the copolymers were determined by elemental analysis, and comonomer reactivity ratios were determined by the Kelen–Tudos (KT) and the error in variable (EVM) methods. The terminal model reactivity ratios obtained from the EVM method are rA = 0.20 and rP = 2.62. The complete spectral assignment of the overlapping proton and carbon spectra of these copolymers were done with the help of distortionless enhancement by polarization transfer and two-dimensional 1H–13C heteronuclear shift correlation (inverse HETCOR) spectroscopy. The assignment of the various conformational and configurational sequences in the proton spectrum were made possible by two-dimensional correlated spectroscopy and total correlation spectroscopy experiments. Monte Carlo simulation was used to study the effect of the degree of polymerization on the triad fractions. © 1998 John Wiley & Sons, Inc. J Appl Polm Sci 69: 2507–2516, 1998