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Volume 46, Issue 7
Displaying 1-13 of 13 articles from this issue
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Mun-soo Lee, Keizo Miyasaka1990 Volume 46 Issue 7 Pages 263-274
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe fine structure of a high-strength homopolymer-type polyacrylonitrile (PAN) fiber prepared by additional heat drawing after usual wet spinning was investigated using wide (WAXD) and small (SAXS) angle X-ray scattering in comparison with those of ordinary homo- and copolymer-type PAN fibers prepared by usual wet spinning method. WAXD data were analyzed by a cylindrical distribution function (CDF) method. The meridional section of CDF showed that the crystal chain has a fiber periodicity of 2.5A in all these three kinds of fibers. The periodicity deteriorated at 12A and 10A in the high-strength homopolymer fiber-type and homo-and copolymer-type fibers. The CDF equatorial section of the high strength homopolymer-type fiber showed peaks at 6.5A, 11.8A and 16.4A. For investigating the long spacing, the meridional SAXS intensity of the fibers was measured before and after thermo-oxidative treatment at 200°C-300°C. Both ordinary homo- and copolymer-type fibers showed SAXS peaks due to the long spacing after oxidative heat-treatment. In the case of high strength homopolymer-type fiber, however, no SAXS peak appeared even after thermo-oxidation. This is the most important structural character of the high strength homopolymer-type fiber.View full abstractDownload PDF (2860K) -
Toshihiko Ohta1990 Volume 46 Issue 7 Pages 275-280
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe mechanism of increase in the initial Young's modulus of Nylon 6 fiber after drawing by water sorption, which occurs during the laying term of its yarn wound in a shape of pirn, was studied. The irreversible shrinkage of drawn yarn occured in the atmosphere of higher humidity than the maximum one in its humidity history. This fact was considered to be due to removal of the internal strain formed during drawing by water sorption. The streching force arose in the drawn yarn wound in a shape of pirn, in stead of the irreversible shrinkage. The yarn in surface layer of a pirn became to show the more water sorption, higher density, higher birefringence and higher Young's modulus than that in the core part with the lapse of its laying days. It was estimated that the more than 77% of amide groups of the Nylon 6 fiber after cold drawing did not form the perfect hydrogen bonding. From the above facts, it was concluded that the water sorbed in Nylon 6 fiber after drawing promoted the stress induced crystallization with the removal of intermolecular distortion, and hence, the increase of initial Young's modulus.View full abstractDownload PDF (453K) -
Tsuyoshi Konomi, Yukiko Yamamoto1990 Volume 46 Issue 7 Pages 281-288
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe sorption behavior of water vapor on wholly aromatic polyamides (Aramides) such as Kevlar 29, Kevlar 49 and Nomex, was investigated, and was compared with that on aliphatic and alicyclic polyamides. The amount of water adsorbed in a monolayer state (vm) was estimated by BET plot for each sample. The ratios of vm to the concentrations of amide groups in amorphous region (vm/18[CONH] (1-α). α; crystallinity), which correspond to the effective number of sorption site for water per amide group in amorphous region, decreased in the following orders; Nomex>Kevlar 29>Nylon 6>Monece>Poly 12 HHTPA for fibers, and Nomex>Kevlar 29>Nylon 2>Nylon 3>Nylon 4>Nylon 6>Poly 12 HHTPA for powder samples. From the analysis using the cluster functions, it was elucidated that the moisture regain at which the water clusters began to arise was somewhat larger than the vm for all the samples. On the other hand, the half-height widths in 1H NMR spectra of adsorbed water in Aramides were narrower than those in other polymers at the same moisture regain. It seems, therefore, that in Aramides the fraction of water molecules tightly bound to amide groups is smaller than that in the other polymers.View full abstractDownload PDF (592K) -
Masakatsu Ohguchi1990 Volume 46 Issue 7 Pages 289-293
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe grafting of acrylic acid (AA) and methacrylic acid (MAA) made poly (ethylene terephthalate) (PET) hydrophilic. The alkali-treatment of the grafted PET enhanced the hydrophilicity, transforming carboxyl groups into their Na-salt form. However, the use of natural water, which contained multi-valent metal ions, in the alkali-treatment of the grafted PET did not bring as high a hydrophilicity as expected. From model reactions in which aqueous CaCl2 solutions was used as media of the alkali-treatment, it became clear that the presence of Ca ions in the alkali-treatment suppressed transforming reaction of carboxyl groups of the grafted PET into the Na-salt form. It was suggested that gel formation of the grafted poly (AA/MAA) shut up the reactive sites, thus preventing transformation of carboxyl groups. The addition of a sequestering agent to the alkali-treating solution was useful in preventing multi-valent metal ion's effect and in bringing about smooth transformation of carboxyl groups into the Na-salt form.View full abstractDownload PDF (1593K) -
Masashi Kobayashi, Masako Sato, Motoi Minagawa1990 Volume 46 Issue 7 Pages 294-300
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSA tension measuring apparatus for the bubble film was developed and the dynamic property of the bubble film generated from solutions of a nonionic surfactant, polyoxyethylene 9-octadecenyl ether, in the absence and the presence of acid dyes (C. I. Acid Red 134 and Green 25) was studied. The apparatus enables the measurement of the dynamic property of the liquid film in the bubble form with separating of the elastic and viscous contribution. Surfactant molecules are preferentially adsorbed to the interface that is newly formed by the extension of the bubble film. In the semi-static condition, however, the existance of the adsorption of C. I. Acid Red 134, with large hydrophobic moiety, on gas-liquid interface is undeniable. In the system that contains surfactant in such a large excess as occurring the large micelle formation, dynamic property of the foam film is not affected by the addition of acid dyes.View full abstractDownload PDF (490K) -
Sukenori Shintaku, Takashi Yamamoto, Toshiyasu Kinari1990 Volume 46 Issue 7 Pages 301-307
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe package enlargement and the increase of production speed have great advantages in the manufacture of highly twisted filament yarn. A new twisting system was proposed in this paper consisting of a flyerless twister containing a false twist spindle, a ring twister, a heater to set yarn and anoter false twist spindle (F2). This twisting system could produce highly twisted yarn without knots wound to a large package. The use of F2 was profitable to reduce the tension of the yarn on the heater. The snarl index of highly twisted yarn was also reduced when F2 was revolved faster than the ring twister spindle. The yarn, set to higher twisted state by F2 and untwisted to the final twist number, had lower torque than that of the yarn with the same twist level obtained by the system without F2. This procedure showed no effect on the twist contraction and heat shrinkage. By this twisting system, twisted yarn with the same level of snarl index as that of yarn produced by the system without F2 was obtainable at lower set temperature. The yarn of lower crystallinity was set to lower torque level, and the fineness of the obtained yarn increased owing to the large heat shrinkage.View full abstractDownload PDF (456K) -
TADASHI MATSUNAGA1990 Volume 46 Issue 7 Pages P280-P282
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
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JUNICHI KOBAYASHI, MASAMI ISHIBASHI1990 Volume 46 Issue 7 Pages P283-P287
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
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EIICHI TAMIYA1990 Volume 46 Issue 7 Pages P288-P291
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
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MEGUMI OKAZAKI1990 Volume 46 Issue 7 Pages P292-P296
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
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SAKUJI NAGASAKI1990 Volume 46 Issue 7 Pages P297-P302
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
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MORIO MIYAGI1990 Volume 46 Issue 7 Pages P303-P308
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
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HIROYUKI NAKAYAMA1990 Volume 46 Issue 7 Pages P309-P314
Published: July 10, 1990
Released on J-STAGE: November 28, 2008
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