Branched Structure of Polyvinyl Acetate

Imoto, Saburo; Ukida, Junji; Kominami, Tsugio

doi:10.1295/koron1944.14.214

Cited by 12 publications

(3 citation statements)

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“…13 Table I lists the values of triad-tacticity estimated from the NMR spectra of 10-% solutions of acetylated samples 14 ' 15 in methylene chloride measured by a Varian HA-100 spectrometer at 60°C. The value of 1,2-glycol content measured by polaro-graphy 16 and the number-average molecular weight Mn of PV A samples estimated from a calibrated GPC curve are also given in Table I.…”

Section: Methodsmentioning

confidence: 99%

Gel Formation and Structure of Junctions in Poly(vinyl alcohol)–Water Systems

Shibatani

1970

Polym J

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The main purpose of this investigation was to elucidate the mechanism of gelation of poly(vinyl alcohol)-water systems and the structure of junctions in gel networks. Changes of gel rigidities were measured as a function of gelling time at the temperatures of 30-80°C for four samples of different tacticities, and the numbers of junctions in the gel were calculated using the theory of rubber elasticity. The formation of junctions can be treated as the binary association of free cross-linking sequences with the activation energy of 13 kcal/mol. The study of the correlation between gelling temperatures and melting temperatures of gels shows that the junctions formed at a given temperature should be treated as multitudinous in structure and the copolymeric character of atactic poly(vinyl alcohol) chains should be considered. The structures of junctions for various gelling temperatures are discussed, assuming that cross-linking loci in poly(vinyl alcohol) chains are syndiotactic sequences of different sequence lengths.

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Section: Methodsmentioning

confidence: 99%

Gel Formation and Structure of Junctions in Poly(vinyl alcohol)–Water Systems

Shibatani

1970

Polym J

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“…The chemical assay method(ref. 13)has usually been. adopted for this determination, but some new method of nondestructive determination has long been sought.…”

Section: 2 Glycol Linkagesmentioning

confidence: 99%

The study of microstructures of poly(vinyl alcohol) by NMR

Amiya¹,

Tsuchiya²,

Qian³

et al. 1990

Pure and Applied Chemistry

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“…Allowing for a 2% variation in the values of [TI, the likely error to be expected in the 1,2-glycol content for polymers containing 1-2y0 of same, on the basis of eqs. (3) and (4), is *0.04% for M , > 50,000, about *0.07% for M o = 10,000, and *0.14% for J40 = 4000 (or a degree of polymerization of ca. 80), as listed in the last column of Table 11.…”

Section: Viscometric Methodsmentioning

confidence: 97%

Determination of 1,2‐glycol units in polyvinyl alcohol

Harris¹,

Pritchard²

1964

J. Polym. Sci. A Gen. Pap.

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A titrimetric method, involving the determination of the periodate consumption by means of iodine and arsenious oxide, was applied to the determination of 1,2‐glycol units in polyvinyl alcohol by periodate cleavage. The method gave consistent results regardless of the molecular weight of the sample, and is believed to be accurate to ±0.05% glycol units. In contrast, it was shown that the well‐known Flory‐Leutner viscometric method gave results which were about 20% lower than those obtained by the first method for samples of molecular weight greater than about 40,000, and gave grossly unrealistic results for samples of much lower molecular weight. Details of the methods and sources of error are discussed.

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Branched Structure of Polyvinyl Acetate

Cited by 12 publications

References 0 publications

Gel Formation and Structure of Junctions in Poly(vinyl alcohol)–Water Systems

Gel Formation and Structure of Junctions in Poly(vinyl alcohol)–Water Systems

The study of microstructures of poly(vinyl alcohol) by NMR

Determination of 1,2‐glycol units in polyvinyl alcohol

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