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Volume 52, Issue 8
Displaying 1-14 of 14 articles from this issue
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Tetsuya Takahashi, Atsuo Konda, Yoshio Shimizu1996 Volume 52 Issue 8 Pages 396-404
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSThe changes of structure and tensile strength and elongation characteristics of polypropylene/polyamide 6 (hereafter “PP/PA6”) blend fibers upon drawing were investigated. Two melting peaks appeared, probably caused by the drawing of the PA6 component. The peak temperature of the PA6 component situated on the lower temperature side increased with increasing drawing ratio and with the PP content. Such melting behavior might be closely related to the crystal perfection and size developed in the PA6 component.
In respect to the crystallinity of the blend fibers, the PA6 component was hardly affected by draw ratio and blend ratio. On the other hand, the PP component exhibited a higher crystallinity by draw. The X-ray diffraction patterns were examined. The undrawn blend fibers exhibited an orientation of PP crystals. However, the DebyeScherrer ring from PP crystals did not disappear even at draw ratio until 4.8. This indicates that the increment of PP crystalline orientation in the blend fibers with draw was smaller than that of the PP fibers.
The tensile strength and elongation characteristics for the blend fibers depended largely on the blend ratios. At a given draw ratio, the strength increased with PA6 content. It was shown that the strength of the blend fibers was largely governed by the content of PA6 component rendering a high strength. The elongation decreased with increasing PA6 content.View full abstractDownload PDF (991K) -
Chan Woo Lee, Yoshihahu Kimura1996 Volume 52 Issue 8 Pages 405-411
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSThe A-B-A tribloc copoly (ester-ether) comprising poly (L-lactide) (A) and poly(oxyethylene-co-oxypropylene) (B) was prepared by copolymerization of L-lactide and a commercially available telechelic copolyether, PluronicrTM (PN) by the catalysis of tin octanoate. The copolymers were melt-spun by the conventional method. Then, the as-spun filament obtained was drawn to 2.5-12.5 times at 40 and 60°C. At a constant draw ratio the tensile modulus of the filament decreased with increasing composition of PN in the copolymer and with increasing draw ratio. Upon immersion in a phosphate buffer (pH=7.4), the filaments showed a time-dependent decrease in tensile strength with accompanying surface erosion. The degradability of the filaments with the same identical copolymer compositions was found to decrease with increasing draw ratio, because of the increased orientational crystallization of PLLA. The block copolymers comprising PLLA and PN, therefore, were shown to have high potentiality as the biodegradable polymers with improved flexibility and biodegradability.View full abstractDownload PDF (1262K) -
Tokie Nakao, Waichiro Tsuji1996 Volume 52 Issue 8 Pages 412-416
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSField-opened American cotton fibers were treated with acrylonitrile after impregnation with aqueous sodium hydroxide. By this treatment the water absorbency and the amount of bound water as determined by DSC were increased and approached those of never-dried cotton. As for tensile strength, the increase in dry strength was higher than that of wet strength. On DSC cooling curves peak II, ascribable to freezable bound water, was observed as a small shoulder for field-opened and mercerized cotton fibers. However, this peak disappeared after the acrylonitrile treatment. Those treated fibers showed a nearly circular cross-sectional shape. Lumen and convolution could hardly be observed.View full abstractDownload PDF (737K) -
Yasuo Matsumura, Kojiro Arai, Kunio Maruyama, Hiroshi Mitomo1996 Volume 52 Issue 8 Pages 417-422
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSQuantitative analysis of water combined with nitrile group, Combined H2O, in acrylic fibers was investigated using infrared spectro-scopical technique, and a practical method was proposed. IR absorbance at 3630cm_??_ was selected as key band for Combined H2O.
Water absorption behavior into acrylic fibers, which were taken at different steps in the wet spinning process, was investigated using this method. The fibers showed different ability of water absorption. Microstructural changes of the fibers caused by conditioning, steam-relaxing and drying of the fiber were discussed in connection with size of microcapillaries in the fiber. A model to explain the behavior was proposed. Combined H2O in the fiber still remained even after vacuum drying at 80°C for 16 hours. It means difficulty to achieve bone-dry state of this fiber by ordinary ways.
Aging of the fiber caused its water absorption ability to increase and it was also attributed to the increase of capillaries' size.View full abstractDownload PDF (427K) -
Tadahisa Iwata, Fumio Tanada, Keizo Okamura, Jun-ichi Azuma1996 Volume 52 Issue 8 Pages 423-429
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSThe single chain conformation of cellulose tributyrate (CTB) and cellulose trivalerate (CTV) has been investigated using MM2 ('87) with Jeffrey's parameter set. The energy surface of CTB had the deepest energy well near twofold screw axis zone. X-ray data supported this result. Two major conformations were found in this energy well. One was just on the twofold screw axis symmetry with exact fiber repeat distance, and the other existed in the lowest energy area just with exact fiber repeat distance. Evaluating the total energy value and torsional angles of side groups, the latter was found superior to the former. On the other hand, the most stable conformation of CTV was satisfied with all three parameters (twofold screw axis symmetry, fiber repeat distance and deepest energy well) on the energy surface. Considering the molecular packing from X-ray patterns, we can predict that both structures have twofold screw symmetry along the molecular axis on the center of two chains.View full abstractDownload PDF (386K) -
Isao Ikeda, Keizo Hashimoto, Ding Xin, Kimihiro Suzuki1996 Volume 52 Issue 8 Pages 430-433
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSLipase-catalyzed transesterification of vinyl acrylate (VA) with D, L-1-phenylethanol was carried out to synthesize D (+)-1-phenylethyl acrylate (PEA) in organic solvents, Lipase OF was the most appropriate enzyme for the synthesis of PEA among four kinds of lipases studied. The conversion to PEA increased with increasing lipase OF concentration. Isooctane was the most appropriate solvent among three kinds of solvents studied. While PEA was synthesized when VA was used as an acylating agent, it was hardly synthesized with acrylic acid or ethyl acrylate. The conversion to 1-phenylethyl methacrylate using vinyl methacrylate or methacrylic anhydride as an acylating agent was much lower than that of PEA. The formation of PEA was confirmed by 1H-NMR spectrum. The optical purity of PEA was 100%. Optically active polymer having molecular weight of about 30, 000 was obtained by a solution polymerization method.View full abstractDownload PDF (269K) -
Ryohei Fukae, Tohei Yamamoto, Yoshitaka Imori, Osamu Sangen, Mikiharu ...1996 Volume 52 Issue 8 Pages 434-440
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESSFiber-forming properties of poly (vinyl alcohol) s (PVAs) with high syndiotacticities (diad syndiotacticity=61-65%) derived from poly (vinyl pivalate) (PVP) were studied. PVA with moderate molecular weight (ca. 7×104), which was derived from PVP, showed a high fiber-formability and provided fibers having a high degree of crystallinity and a high mechanical strength. One the other hand, PVAs having fairly high molecular weights (>4×105) and having high syndiotacticities were less drawable owing to the strong intermolecular forces caused by the stereoregularity.View full abstractDownload PDF (763K) -
Taeko Kitaura, Toshihiko Amano1996 Volume 52 Issue 8 Pages 441-446
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
JOURNAL FREE ACCESS“Promix” fiber is a so-called silk-like fiber. Enzyme treatment of this fiber with proteases on market was studied in order to improve the water absorptivity of the fiber. Several experiments using various proteases on market lead a conclusion that the fiber was pre-treated with phosphoric acid, and then treated with Enchiron PN-10L, a neutral protease. Selecting suitable treatment conditions, the water absorptivity of “Promix” fiber increased higher than twice as that of the untreated fiber. For silk and Nylon fibers the improvement of the water absorptivity was taken place to some extent, but not so high for “Promix” fiber. The treatment did not generate little change in molecular structures and macroscopic morphology of the fibers. The effect of the treatment was mainly evaluated with the absorptivity of the dyestuff to the fibers. The dyestuff absorptivity to the fibers indicated a linear relationship to the water absorptivity. This fact suggests that the dyestuff absorptivity at room temperature was a good measure for the water absorptivity of the fibers. The measurements of the dyestuff absorptivity at room temperature is much easier and more practical than that of the water absorptivity. The control of the water absorptivity is important for improving the fiber properties. The enzyme treatment was found an effective improving means without changing other characteristics for particular man-made fibers like “Promix” fiber. Moreover, the enzyme treatment can be expected to play a role in improving the dyeability at low temperature and some physical properties, such as the fabric handle.View full abstractDownload PDF (399K) -
TAKASHI FUJIMAKI1996 Volume 52 Issue 8 Pages P320-P325
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
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MINORU NAKAMURA1996 Volume 52 Issue 8 Pages P326-P330
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
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MITSURU OSAWA1996 Volume 52 Issue 8 Pages P331-P335
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
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OSAMI KAMIGAITO1996 Volume 52 Issue 8 Pages P336-P340
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
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YOSHIHANU KIMURA1996 Volume 52 Issue 8 Pages P341-P346
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
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KAZUO MURATA1996 Volume 52 Issue 8 Pages P347-P350
Published: August 10, 1996
Released on J-STAGE: June 30, 2008
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