<sup>13</sup>C- and <sup>1</sup>H-NMR Investigations of Sequence Distribution in Vinyl Alcohol-Vinyl Acetate Copolymers

Moritani, Tōhei; Fujiwara, Yuzuru

doi:10.1021/ma60057a007

Cited by 105 publications

(124 citation statements)

References 6 publications

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“…These three signals, therefore, can be assignable to the three compositional dyads of (VA,VA), (VA,VL) and (VL,VL) in order of decreasing frequency, where VA, and VL denote vinyl alcohol unit and vinyl levulinate unit, respectively. The chemical shift dependence on the degree of esterification is very much similar to those of vinyl alcohol-vinyl acetate copolymers [47,48,[51][52][53][54][55] and vinyl alcohol-vinyl propionate copolymers [56].…”

Section: Reaction Timementioning

confidence: 56%

“…1 shows the 1 H NMR spectra of a sample of VA-VL copolymer, LA and PVA together with the assignment of signals in the copolymer. The copolymer provides not only the signals due to the feature of the original PVA backbone structure [47][48][49] but also the signals due to levulinate group. The signals at 2.10 ppm and a set of 2.43 and 2.69 ppm in the spectrum of the copolymer are attributable to the methyl and two methylene protons of levulinate unit [50], respectively.…”

Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 99%

“…The broad multiplet signal at the region from 1.2 to 1.9 ppm is due to methylene protons in the copolymer backbone. The multiplet signals centered at 3.76 ppm and at 5.02 ppm are assignable to two kinds of methine protons bearing hydroxyl groups and the levulinate units in the backbone, respectively [47][48][49].…”

Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 99%

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N,N-dicyclohexylcarbodiimide assisted synthesis and characterization of poly(vinyl alcohol-co-vinyl levulinate)

Wang

Ikeda

Hori

et al. 2005

Polymer

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Section: Reaction Timementioning

confidence: 56%

Section: Differential Scanning Calorimetry (Dsc)mentioning

confidence: 99%

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N,N-dicyclohexylcarbodiimide assisted synthesis and characterization of poly(vinyl alcohol-co-vinyl levulinate)

Wang

Ikeda

Hori

et al. 2005

Polymer

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“…The degree of transformation can be easily followed by the disappearance of the methyl protons in the acetate group: the signal at about 1.97 ppm (the chemical shift of this resonance is dependent on both solvent and temperature 12) ). The methine protons can be also monitored: the signals at about 5 and 3.5 ppm correspond, respectively, to the methines adjacent to an acetate or a hydroxyl group [13][14][15] . Fig.…”

Section: Resultsmentioning

confidence: 99%

Preparation and properties of terpolymers of ethylene, vinyl acetate and vinyl alcohol

Pérez

Luján

Salazar

2000

Macromol. Chem. Phys.

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Several terpolymers of ethylene, vinyl acetate and vinyl alcohol have been prepared by controlled transformation into hydroxyls of the acetate groups of an ethylene‐vinyl acetate copolymer (with 28 wt.‐% in vinyl acetate). The degree of transformation has been determined by 1H NMR. Samples covering the entire range of transformations have been obtained, and their properties have been analyzed by DSC and X‐ray diffraction. The results show a marked increase of both melting temperature and crystallinity as the degree of transformation increases, owing to the fact that the vinyl alcohol units are able to cocrystallize in the polyethylene lattice, while the acetate groups are excluded.

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“…The average number of successively aligned hydroxyl group or mean run length L OH can be a measure for the flexibility of hydrogen bonding. L OH in PVAL-AC (AC 12 mol%) and PVAL-VP (VP 5 mol%) can be calculated as 14 and 20 when the block characters, Z, indicating the distribution of acetyl or VP units, are assumed as 0.6 and 1, respectively [22]. Smaller amounts of VP units in PVAL-VP can work efficiently by reducing the mean run length of hydroxyl groups more effectively than the reduction by the acetyl group in PVAL-AC because the acetyl groups distribute in a blockier fashion while VP tends to distribute more randomly.…”

Section: Dsdna Capillary Electrophoresismentioning

confidence: 99%

DNA capillary electrophoresis using poly(vinyl alcohol). II. Separation media

Moritani¹,

Yoon²,

Chu

2003

Electrophoresis

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DNA capillary electrophoresis using poly(vinyl alcohol). II. Separation mediaWe represent the first extensive study on DNA capillary electrophoresis using various poly(vinyl alcohol) (PVAL)-related polymers as separation media. As a separation medium, PVAL homopolymer has shown poor resolutions probably due to its very strong hydrogen-bonding characteristics, resulting in extensive self-aggregation. On the other hand, poly(vinyl alcohol-co-vinyl acetate) and poly(vinyl alcohol-co-1-vinyl-2-pyrrolidone) (PVAL-VP), both with a degree of polymerization of ,3.0610 3 , have been found to give excellent electropherograms with good resolutions for the analysis of double-stranded (ds)DNA. PVAL-VP, with hydrolytic stability in high and low pH regions, has also yielded fair electropherograms for single-stranded (ss)DNA under neutral and alkaline conditions, although further investigation is essential in order to increase the resolutions necessary for DNA sequencing analysis. The separations obtained under alkaline conditions have shown significantly shorter retention times, one-third of that for the current commercial separation media, due to the higher ionization of phosphate groups in the DNA chains. IntroductionDuring the recent marked advances in capillary electrophoresis (CE), a number of water-soluble polymers have been investigated as separation media: poly(N,N'-dimethylacrylamide) (PDMA), poly(acrylamide) (PAM), agarose, hydroxyethylcellulose (HEC), polyethylene glycol (PEG), poly(vinylpyrrolidone) (PVP), pluronic polyols, etc. [1][2][3][4]. However, only two papers have been published on the application of poly(vinyl alcohol) (PVAL) in CE, in spite of its apparent suitability as a typical nonionic water-soluble synthetic polymer. Simò-Alfonso et al. [5] have reported successful results for proteins using PVAL (M r 133 000), which offers excellent resolutions in 4-6 wt% solutions and shows sieving effects even in extremely dilute solutions, with concentrations of ,1 wt%, that is much lower than the observed threshold of 3 wt% from the viscosity data. Kleemiss et al. [6] have shown deterioration of resolution about the CE of double-stranded (ds)DNA using the PVAL of M r 50 000 and hydrolysis grade 99%, with bare fused-silica capillaries. They ascribed the negative results to strong self-aggregation of PVAL by hydrogen bonding. Both previous works have attributed the specific characteristics of PVAL to hydrogen bonding, which should be controlled in the application to CE.PVAL is believed to have a significant potential in CE because it has an advantage of the hydrolytic stability all over pH ranges, together with additional advantages, such as moderate viscosities, environmental friendliness of nontoxic and biodegradable properties, and full transparency in the UV region down to 200 nm [5]. The intrinsic chemical stability of PVAL is useful for expanding applications of CE to higher and lower pH regions for the separations and analyses of DNA fragments, proteins, and other charged molecules. In particular, alkaline...

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¹³C- and ¹H-NMR Investigations of Sequence Distribution in Vinyl Alcohol-Vinyl Acetate Copolymers

Cited by 105 publications

References 6 publications

N,N-dicyclohexylcarbodiimide assisted synthesis and characterization of poly(vinyl alcohol-co-vinyl levulinate)

N,N-dicyclohexylcarbodiimide assisted synthesis and characterization of poly(vinyl alcohol-co-vinyl levulinate)

Preparation and properties of terpolymers of ethylene, vinyl acetate and vinyl alcohol

DNA capillary electrophoresis using poly(vinyl alcohol). II. Separation media

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13C- and 1H-NMR Investigations of Sequence Distribution in Vinyl Alcohol-Vinyl Acetate Copolymers

Cited by 105 publications

References 6 publications

N,N-dicyclohexylcarbodiimide assisted synthesis and characterization of poly(vinyl alcohol-co-vinyl levulinate)

N,N-dicyclohexylcarbodiimide assisted synthesis and characterization of poly(vinyl alcohol-co-vinyl levulinate)

Preparation and properties of terpolymers of ethylene, vinyl acetate and vinyl alcohol

DNA capillary electrophoresis using poly(vinyl alcohol). II. Separation media

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Product

Resources

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¹³C- and ¹H-NMR Investigations of Sequence Distribution in Vinyl Alcohol-Vinyl Acetate Copolymers