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271.
A. S. Brar S. K. Hekmatyar 《Journal of polymer science. Part A, Polymer chemistry》1999,37(6):721-727
Acrylonitrile‐Styrene (A/S) copolymers were prepared by photopolymerization using uranyl nitrate ion as initiator. The copolymer compositions were determined by elemental analysis, and comonomer reactivity ratios were determined by nonlinear least squares error in variables method (EVM). The complete spectral assignment of the 13C and 1H‐NMR spectra were done with the help of Distortionless Enhancement by Polarization Transfer (DEPT) and by the two dimensional 13C‐1H Heteronuclear Single Quantum Correlation (HSQC) and TOCSY experiments. The methylene and methine carbon resonance show both stereochemical and compositional sensitivity. The 2‐D Total Correlated Spectroscopy (TOCSY) experiment was used to ascertain the various geminal coupling between the methylene protons. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 721–727, 1999 相似文献
272.
A. S. Brar Kaushik Dutta S. K. Hekmatyar 《Journal of polymer science. Part A, Polymer chemistry》1998,36(7):1081-1092
The acrylonitrile/methyl methacrylate copolymers of different monomer concentration were prepared by photo polymerization using uranyl ion as initiator. The carbon 13 and proton spectra of these copolymers are overlapping and complex. The complete spectral assignment of the 13C- and 1H-NMR spectra were done with the help of Distortionless Enhancement by Polarization Transfer (DEPT) and two dimensional 13C–1H Heteronuclear Single Quantum Correlation (HSQC) experiments. The methylene, methine and the methyl carbon resonances show both stereochemical (triad level) and compositional (dyad, triad, tetrad, pentad and hexad level) sensitivity. 2D Double Quantum Filtered Correlated Spectroscopy (DQFCOSY) experiment was used to ascertain the various geminal couplings between the methylene protons. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1081–1092, 1998 相似文献
273.
Copolymer compositions and reactivity ratios for the radical copolymerization of styrene with acrylonitrile have been determined by x-ray photoelectron spectroscopy (XPS). The results obtained by this technique were confirmed by elemental as well as 1H-NMR (nuclear magnetic resonance) analysis. The monomer sequence distributions have also been calculated utilizing the monomer reactivity ratio values obtained by three different techniques viz., XPS, 1H-NMR, and elemental analysis. The agreement between the monomer sequence distributions in the copolymer chain by these methods is very satisfactory. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2049–2056, 1997 相似文献
274.
《Mendeleev Communications》2023,33(4):568-571
The copolymers of acrylonitrile and 1-vinylimidazole with a narrow molecular weight distribution (MWD) were synthesized for the first time by the reversible addition–fragmentation chain transfer (RAFT) polymerization in a DMSO solution in the presence of acetic acid. Their thermal behavior difference upon heating in argon and in air along with ability to melt make them promising precursors for carbon fiber production. 相似文献