Kobunshi Kagaku

Dielectric Studies on Fibers

II. Dielectric Measurements of Viscose Rayon at Low Frequencies

Yoichi Ishida, Suguru Machida, Motoo Takayanagi, Fujio Irie

1957 Volume 14 Issue 142 Pages 71-78
Published: February 25, 1957
Released on J-STAGE: October 14, 2010

DOIhttps://doi.org/10.1295/koron1944.14.71

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In order to inquire into the relationship between the fine structure and dielectric properties of fiber, the authors studied at low frequency region on several kinds of treated samples of viscose rayon, the fine structure of which had been transformed by annealing or hydrolysis. Analysing the results by the method of plotting complex resistivity referred to in the first report, the authors could represent the frequency characteristics of the samples in a simple equivalent circuit. Further, the authors inquired into the relationship between the electric circuit constants thus obtained on the samples and the results of the measurement of degree of polymerization, density and moisture regain.

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Studies on Acrylonitrile Polymerization

III. Inhibition Period of Redox Polymerization

Isamu Yamazaki

1957 Volume 14 Issue 142 Pages 79-86
Published: February 25, 1957
Released on J-STAGE: October 14, 2010

DOIhttps://doi.org/10.1295/koron1944.14.79

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The inhibition period of acrylonitrile polymerization initiated mainly by the K₂S₂O₈-AgNO₃ redox recipe was investigated in various conditions. It was extremely shortened by adding a very small quantity of AgNO₃, and it was proportional to the inhibitor-concentration and to the reciprocals of both the activator and the initiator-concentrations, but was indistinctly affected by the monomer concentration under various temperatures.

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Studies on Acrylonitrile Polymerization

IV. The Effect of Divinyl-acetylene on the Redox Polymerization

Isamu Yamazaki

1957 Volume 14 Issue 142 Pages 86-91
Published: February 25, 1957
Released on J-STAGE: October 14, 2010

DOIhttps://doi.org/10.1295/koron1944.14.86

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In the presence of divinyl acetylene, acrylonitrile was polymerized by three typical redox recipes such as K₂S₂0₈-AgNO₃, -NaHS0₃, and-Hydroquinone systems. These redox-polymerizations were inhibited proportinally to the quantity of added divinyl acetylene, and both the monomer consumption rate and the degree of polymerization were reduced considerably. The initiating power of these redox system was compared under the same concentration of each reductant.

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Studies on the Swelling of Polyvinyl Alcohol

V. Influence of the Removal of Soluble Parts on the Effect of the Heat Treatment of Polyvinyl Alcohol Films

Yasuo Sone, Ichiro Sakurada

1957 Volume 14 Issue 142 Pages 92-96
Published: February 25, 1957
Released on J-STAGE: October 14, 2010

DOIhttps://doi.org/10.1295/koron1944.14.92

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Films were prepared from a fractionated polyvinyl alcohol of DP 1288, subjected to a light heat treatment at 40°C for 10 minutes and then immersed in water at 30°C for the removal of water soluble parts of films. The extracted films were then air dried and subjected to heat treatment at 40, 80, 120, 160 and 200°C for 10 minutes. Original films were also similary treated and the swelling, solubility and density of the two series of films were compared. In the case of heat treatment at lower temperature, there was a distinct difference between the two series. Extracted films showed lower swelling and higher density and crystallinity. Similar experiments were also carried out with an unfractionated polyvinyl alcohol of DP 1550 to obtain similar results.

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Studies on the Swelling of Polyvinyl Alcohol

VI. Swelling of Films Prepared from Water-Soluble and Insoluble Parts of Polyvinyl Alcohol Films

Yasuo Sone, Ichiro Sakurada

1957 Volume 14 Issue 142 Pages 96-100
Published: February 25, 1957
Released on J-STAGE: October 14, 2010

DOIhttps://doi.org/10.1295/koron1944.14.96

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A fractionated polyvinyl alcohol of DP 720 was used as a starting substance and according to the method given in the previous report separated into water-soluble and insoluble parts. DP's of the water soluble and in soluble parts were 540 and 770 respectively. Films were prepared from these two kinds of polyvinyl alcohol and subjected to heat treatment to compare swelling, solubility and crystallinity. In the case of heat treatment at lower temperature, there was a distinct difference between the two.Films from water soluble part showed higher swelling and lower density and crystallinity. It was attributed not to the difference of molecular structure but to the difference of molecular weight.

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Branched Structure of Polyvinyl Acetate

I. Polymerization of Vinyl Trimethylacetate in the Presence of Polyvinyl Acetate

Saburo Imoto, Junji Ukida, Tsugio Kominami

1957 Volume 14 Issue 142 Pages 101-106
Published: February 25, 1957
Released on J-STAGE: October 14, 2010

DOIhttps://doi.org/10.1295/koron1944.14.101

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For studying the branching of polyvinyl acetate (PVAc) and polyvinyl alcohol (PVA), the polymerization of vinyl trimethylacetate in the presence of PVAc was examined. The differences between PVAc and polyvinyl trimethylacetate (PVTMAc) are as follows: 1 PVTMAc is thoroughly insoluble in 25 aqueous methanol. 2. The rate of alkali-catalized saponification of PVTMAc is remarkably slower than that of PVAc. 3. The infra-red absorption band at 12.49 tt for PVAc and the band at 13.05μ for PVTMAc are the key bands.From these bands, the chemical composition of graft polymer can be determined. From these results, the graft copolymer of PVTMAc into PVAc was separated and saponified in order to examine the branching of PVAc and PVAc. Consequently, it has been shown that methyl group of the acetyl radical in PVAc is the principal site of branching and tertiary hydrogen atom also makes a small contribution.

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Studies on Free Rtdical Polymerizations by the Measurement of Kinetic Chain Lifetimes

I. Effect of Carbon Tetrachloride on Styrene Polymerization

Saburo Fujii, Satohiro Tanaka

1957 Volume 14 Issue 142 Pages 107-116
Published: February 25, 1957
Released on J-STAGE: October 14, 2010

DOIhttps://doi.org/10.1295/koron1944.14.107

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The average lifetimes of kinetic chains in the photo-polymerization of styrene with and without carbon tetrachloride have been measured, at various conversions, in order to find the factors of controlling chain termination. Under our experimental conditions, the photo-rate is found to be sensitized with carbon tetrachloride, and the low conversion results show a difference in k_p/k_t, the rate constant ratio of chain propagation to termination, between the unsensitized and sensitized systems. At high conversions, both the rate and the lifetime increase remarkably for the unsensitized system, while these increases are considerably diminished in the presence of carbon tetrachloride. Analysis of our data indicates the marked effect of bulk viscosity on the termination reaction and also suggests, under several assumptions, that the magnitude of k_t at a given high viscosity depends on the chain-transfer probability of polystyrene radicals.

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Erratum to : On the Crease Recovery of Fabrics

1957 Volume 14 Issue 142 Pages 116
Published: 1957
Released on J-STAGE: October 14, 2010

DOIhttps://doi.org/10.1295/koron1944.14.142_116

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