Sequencing of trans-4-methacryloyloxyazobenzene/vinylidene chloride copolymers by one- and two-dimensional NMR spectroscopy

✍ Scribed by A. S. Brar; M. Thiyagarajan

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 210 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19990815)37:16<3179::aid-pola15>3.0.co;2-h

✦ Synopsis

Trans-4-methacryloyloxyazobenzene/Vinylidene Chloride (M/V) copolymers of different monomer concentrations were prepared by solution polymerization using benzoyl peroxide as an initiator. The copolymer composition was determined from the 13 C{ 1 H}-NMR spectrum. The quaternary carbon of M-and V-centered resonances were used for determining the sequences in terms of the distribution of M-and V-centered triads. The sequence distribution of M-and V-centered triads determined from 13 C{ 1 H}-NMR spectra of the copolymer is in good agreement with the triad concentration calculated from the statistical model. The comonomer reactivity ratios, determined by both the Kelen Tudos (KT) and the nonlinear error in variables (EVM) methods are r M ϭ 3.59 Ϯ 0.19, r V ϭ 0.89 Ϯ 0.07; r M ϭ 3.76, and r V ϭ 0.93, respectively. 13 C Distortionless Enhancement by Polarization Transfer (DEPT) spectrum was used to differentiate between the resonance signals of M-and V-methylene and methyl carbon units. Assignments to the methylene resonance signals have been assigned up to the tetrad levels using 2D HSQC experiments. The geminal couplings in the methylene proton region is shown in the 2D DQF-COSY spectrum.