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

✍ Scribed by A. S. Brar; Kaushik Dutta

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 293 KB
• Volume: 69
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19980919)69:12<2507::aid-app22>3.0.co;2-s

✦ Synopsis

The chemical microstructure of acrylonitrile-pentyl methacrylate (A-P) copolymers prepared by photopolymerization using uranyl ion as the photo sensitizer is analyzed by 13 C{ 1 H} 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 r A Å 0.20 and r P Å 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 1 H-13 C 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.