Nuclear magnetic resonance investigation of the microdynamics of vinyl chloride-vinylidene chloride copolymers

Menge, H.; Schneider, H.

doi:10.1016/0032-3861(93)90178-d

Cited by 3 publications

(2 citation statements)

References 23 publications

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“…The detailed analysis of relaxation data determined in a number of polymer systems, 9,[15][16][17][18][19][20][21][22] either in solution or in bulk at temperatures well above the glass transition temperature, has shown that the local motions observed by 13 C spinlattice relaxation can be satisfyingly described in terms of damped diffusion of bond orientation along the chain sequence, which represents the segmental motions, and independent fast bond librations. 9 The corresponding orientation autocorrelation function is written as…”

Section: -mentioning

confidence: 99%

Local dynamics of isotactic and syndiotactic polypropylene in solution

Destrée

Lauprêtre

Lyulin

et al. 2000

The Journal of Chemical Physics

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The local dynamics of polypropylene ͑PP͒ in solution is studied by 13 C NMR relaxation and by molecular dynamics ͑MD͒ simulation via the orientational autocorrelation function ͑OACF͒ of C-H bonds. The interpretation protocol of this function proposed by Dejean de la Bâtie, Lauprêtre and Monnerie ͑DLM͒ ͓R. Dejean de la Bâtie, F. Lauprêtre, and L. Monnerie, Macromolecules 21, 2045͑1988͔͒ is applied and tested on new NMR measurements of the various microstructures of polypropylene. This interpretation scheme of the OACF is supported by a detailed study employing simulated PP trajectories in an atomistic heat bath. MD simulations indicate that, quite generally, the correlation time for segmental motions, 1 , extracted from the DLM motional model is closely linked with the mean time between conformational jumps. Both experiments and simulations suggest a slightly higher mobility of meso sequences by comparison with racemic sequences. Our analysis of the microscopic aspects of the segmental dynamics and its manifestation in motional models allows us to trace the microscopic origin of the larger mobility of meso sequences.

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Section: -mentioning

confidence: 99%

Local dynamics of isotactic and syndiotactic polypropylene in solution

Destrée

Lauprêtre

Lyulin

et al. 2000

The Journal of Chemical Physics

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“…Kamide et al 4 made the assignments of the 13 C NMR spectrum of acrylonitrilevinylidene chloride copolymer and reported its sequence distribution. Cais et al 5 investigated the microstructure of vinylidene halide and vinyl halide copolymers, whereas the microdynamical study of vinylidene chloride-vinyl chloride copolymer was undertaken by Menge et al 6 The physical aspects like shear degradation, 7 crystallization kinetics, 8 structure, morphology, 9 and thermal behavior of vinylidene chloride-methyl acrylate have been studied. 10 Two-dimensional (2D) NMR experiments 11,12 have been used as the most reliable method for determining the conformational 15 and configurational 16 microstructure of the copolymers.…”

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confidence: 99%

Compositional Assignments and Sequence Distribution of Vinylidene Chloride−Methyl Acrylate Copolymers Using One- and Two-Dimensional NMR Spectroscopy

Brar

Malhotra

1996

Macromolecules

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The microstructure of vinylidene chloride−methyl acrylate copolymers prepared by a photopolymerization process using uranyl ion as photosensitizer is analyzed by one- and two-dimensional NMR spectroscopy. Sequence distribution was calculated from 13C{H} NMR spectra of the copolymers. A 13C distortionless enhancement by polarization transfer spectrum was used to differentiate between the resonance signals of methoxy and methylene units in the copolymer. Comonomer reactivity ratios were determined using Kelen−Tudos and the nonlinear error in variables methods. The sequence distribution of vinylidene chloride- and methyl acrylate-centered triads determined from 13C{1H} NMR spectra of copolymers is in good agreement with triad concentrations calculated from statistical model and Monte Carlo simulation methods. 2D heteronuclear single quantum correlation and correlated spectroscopy spectrum was used to analyze the complex 1H NMR spectrum.

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trans-4-Acryloyloxyazobenzene/Vinylidene Chloride Copolymers. Nuclear Magnetic Resonance Characterization

Brar

Thiyagarajan

1999

Polym J

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ABSTRACT:trans-4-Acryloyloxyazobenzenelvinylidene chloride (A/V) copolymers of different monomer concentrations were prepared by solution polymerization using benzoyl peroxide as initiator. The copolymer composition was determined from the quantitative 13 C{'H} NMR spectrum. The carbonyl carbon of A-and the quaternary carbon of V-centered resonances were used for determining the sequences in terms of the distribution of A-and V-centered triads. The sequence distribution of A-and V-centered triads determined from 13 C{'H} NMR spectrum of the copolymer is in good agreement with triad concentration calculated from statistical model. The comonomer reactivity ratios, determined by both Kelen-Tiidos (KT) and nonlinear error in variables (EVM) method are rA =0.36±0.03, rv = 1.02±0.06; rA =0.37 and rv= 1.04, respectively. 13 C Distortionless enhancement by polarization transfer (DEPT) spectrum was used to differentiate the resonance signals of methine (A) and methylene carbon signals of A-and V-units. Assignments to the methinc and methylene resonance signals have been assigned up to the tetrad levels using 2D HSQC experiments. The geminal coupling in the methylene and methine proton region is shown in the 2D TOCSY spectrum.KEY WORDS 13 and trans-4-methacryloyloxyazobenzene/menthyl methacrylate copolymer. 14 The chiroptical properties and photochromic behavior of the copolymers were reported by AI tomare e t a!. 15 To the best of our knowledge, the detailed microstructure study of trans-4-acryloyloxyazobenzenejvinylidene chloride (A/V) copolymers have not been reported so far. In this work, we report the stereochemical structure and sequence distribution of (A/V) copolymers by one and two-dimensional NMR spectroscopy. The 1 H NMR spectrum of copolymer is complex and hasTo whom all correspondence should be addressed. 1224been interpreted with the help of 2D heteronuclear single quantum correlation (HSQC) NMR spectroscopy. The reactivity ratios of the comonomers have been calculated using Kelen-Tiidos (K T) 16 and the non-linear Error in Variable Model (EVM) 17 methods, using the compositional data. The A-and V-centered triad sequence distribution obtained from 13 C{ 1 H} NMR spectrum and are compared with those calculated from the first order Markov model using reactivity ratios determined from the EVM 18 method. EXPERIMENTALThe details of the copolymerization process and NMR measurements are explained in our earlier publications. 19 · 20 RESULTS AND DISCUSSION Reactivity Ratios DeterminationThe copolymer composition of the A/V copolymers were determined from the quantitative 13 CCH} NMR spectra using the inverse gated decoupling pulse program with 8 s as delay time. Table I shows the comonomers mole fractions in the feed and in the copolymer. The initial estimate of the reactivity ratios was done by the KT method. The values of the terminal model reactivity ratios obtained from the KT plot are r A= 0.36 ± 0.03 and rv = 1.02 ± 0.06. These values along with the copolymer data were used to calculate the reactivity rat...

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Nuclear magnetic resonance investigation of the microdynamics of vinyl chloride-vinylidene chloride copolymers

Cited by 3 publications

References 23 publications

Local dynamics of isotactic and syndiotactic polypropylene in solution

Local dynamics of isotactic and syndiotactic polypropylene in solution

Compositional Assignments and Sequence Distribution of Vinylidene Chloride−Methyl Acrylate Copolymers Using One- and Two-Dimensional NMR Spectroscopy

trans-4-Acryloyloxyazobenzene/Vinylidene Chloride Copolymers. Nuclear Magnetic Resonance Characterization

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