Sen'i Gakkaishi
Online ISSN : 1884-2259
Print ISSN : 0037-9875
Volume 27, Issue 1
Displaying 1-5 of 5 articles from this issue
  • Haruko Sasano, Toru Kawai
    1971 Volume 27 Issue 1 Pages 1-10
    Published: January 10, 1971
    Released on J-STAGE: November 28, 2008
    JOURNAL FREE ACCESS
    Uniaxial elongation of a commercial polyethylene film having the so-called a-axis orientation along the machine direction was studied in terms of the changes occuring in the crystalline orientation as revealed by the X ray method at small and wide angles and those in the orientation in the disordered region by the shrinkage of the drawn film. The results obtained are as follows: 1) The original “a-axis orientation” tends to the c-axis orientation as the draw ratio (D. R.) is increased beyond the yield point(D. R.=ca. 1.2 at room temperature) but in the intermediate stage up to ca 1.5 of D. R. the two types of orientations coexist. 2) The small angle scattering patterns are always on the meridian throughout the drawing process, implying that lamellae are piled up along the machine (or drawn) direction. 3) In the case of the elongation at room temperature, the X ray long spacing increases first with the increasing D. R., showing a maximum increase of ca. 14%, which corresponds to the macroscopic elongation at the yield point, and then drops gradually. 4) When the film was drawn at higher temperatures (80_??_130°C), a similar maximum in the long spacing appears at higher D. R. and further elongation gives rise to a rapid drop in the long spacing and then to a levelling off in the D. R. range beyond ca. 100_??_120%. This constant long spacing is dependent only on the drawing temperature; the higher the temperature, the higher the long spacing, irrespective of the original spacing, suggesting strongly the melt-recrystallization mechnism occuring in the drawing process. 5) When the film drawn at room temperature, was heated at the fixed length to a given temperature, the long spacing increases up to that of the film drawn at the corresponding high temperature. 6) The contraction of the drawn film on relaxing proceeds rather repidly (ca. within 100 min) even at the room temperature. The equilibrium contraction shows a maximum (ca. 37%) at 110% elongation for the film drawn at room temperature at the rate of 25%/min. A similar maximum, though a smaller contraction, occures at lower elongation for the film drawn at higher temperatures as measured at room temperature, suggesting the relaxation (or the coiling of the disordered tie chains) took place already at the drawing temperature. All the above results suggest that up to the yield point the elongation occurs only in the disordered region (the tie chains) and after the transitional stage where partial melting and reorganization also likely take place, the final steady state (at least locally in the microscopic neck) of the melt-recrystallization is attained, The intermediate transitional stage may cover a wider range of elongation at lower drawing temperature.
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  • Sadao Hibi, Matso Maeda, Masaharu Mizuno, Shunji Nomura, Hiromichi Kaw ...
    1971 Volume 27 Issue 1 Pages 11-19
    Published: January 10, 1971
    Released on J-STAGE: November 28, 2008
    JOURNAL FREE ACCESS
    In the case of the orientation evaluation of non-crystalline region of the uni- and bi-axially stretched crystalline polymer, the evaluation of molecular orientation can be made by the measurement of the visible dichroism or the infrared dichroism. However, we have not obtained the information concerned with the dyed mechanism between the non-crystalline chain and the dye molecule. In order to explore the mechanism, a single crystal of Congo Red was prepared, and then the visible dichroism and/or the infrared spectra of the crystal were measured. By using these results, we determined the dichroism of the characteristic absorption band of the crystal.
    Finally, the birefringence, infrared diohroism, orientation factor of crystalline region and crystallinity were measured for the highly stretched PVA film in which large amount of the dye were dissolved.
    From the results, the angle between the non-crystalline chain and the dye molecule was determined on the basis of the additivity of birefringence.
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  • Sadao Hibi, Matsuo Maeda, Masanori Takeuchi, Shunji Nomura, Yuzo Shiba ...
    1971 Volume 27 Issue 1 Pages 20-29
    Published: January 10, 1971
    Released on J-STAGE: November 28, 2008
    JOURNAL FREE ACCESS
    The orientation behaviors of crystalline and non-crystalline phases of uniaxially stretched PVA dyed with Congo Red, were observed by means of simultaneous measurements of X-ray diffraction, visible dichroic ratio and birefringence.
    The following results were obtained:
    1) The orientation behavior of crystallites in the dfferent degree of crystallinity of the polymers, such as higher crystallinity polymers, the preferential orientation of crystallites with stretching, especially at low degrees of stretching, were observed.
    2) For the stretched specimens at a released state, we could not recognize clearly the effect of crystallinity, through the measurementsof visible dichroic ratio.
    3) The decrease in crystallinity during the uniaxially stretching, were considerable in the higher degree specimens.
    4) As a result of the orientation evaluation of crystalline and non-crystalline phases, it was found that the rod floating model is available for the consideration of crystalline orientation behavior.
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  • Shiro Takahashi, Akira Takahashi
    1971 Volume 27 Issue 1 Pages 30-34
    Published: January 10, 1971
    Released on J-STAGE: November 28, 2008
    JOURNAL FREE ACCESS
    Two type of oxycellulose films (20μ in thickness) containing uronic and nonuronic carboxyl groups were reacted with various metallic salt solutions, and the effects of pH, of the concentration of the solution and also of the solvent added on ion-exchange reaction were studied by infrared spectrometry.
    1) For analyzing the carboxyl group in cellulose spectrometrically, it is obviously preferable to determine the absorbance due to ν C=O of the samples after ion exchange.
    2) Both uronic and nonuronic carboxyl groups in cellulose behaved as a weakly acidic cationexchanger in the reaction with various metallic salts.
    3) The effects of the cations and anions of various metallic salts on ion exchange capacity were as follows;
    4) Uronic and nonuronic carboxyl groups in cellulose were separated from each other by the exchange reaction with alcoholic or acetonic aqueous solution of aluminium nitrate.
    * Study of Oxycellulose Part 10
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  • Nobumasa Hojo, Hirofusa Shirai, Yasuyoshi Nakamura
    1971 Volume 27 Issue 1 Pages 35-39
    Published: January 10, 1971
    Released on J-STAGE: November 28, 2008
    JOURNAL FREE ACCESS
    The gelation from silk fibroin aqueous solution in the prseence of copper (II) ion was investigated under various conditions (pH and ion concentration). The rate of gelation are closely related to pH and ion concentration of copper (II). The infrared spectra and X-ray analysis showed that the erystals have the cross β structure in all the films formed from the gels. The content of β-form in the gels obtained in the presence of copper II ion does not change after removing the ion by adding ethylenediamineteraacetic acid to the gel. The time depency of the reduced viscocity of silk fibroin aqueous solution was studied in the presence of copper (II) ion with pH below 8.5 In relation between viscosity and standing time, it was observed that after decreasing gradually, the reduced viscosity increased again, and gels were formed. On the basis of the results mentioned above, the effect of copper (II) ion on the random→β denaturation of silk fibroin aqueous solution is discussed.
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