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Volume 52, Issue 7
Displaying 1-11 of 11 articles from this issue
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Saburou KUBOTA1995 Volume 52 Issue 7 Pages 395-401
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPolynorbornen (PNR) filled with a large amount of lead (Pb) powder was prepared in the presence of aromatic process oils. The mechanical loss tangent (tan δ) and sound transmission loss (TL) were studied for the PNR-Pb compound sheets. The mechanical tanδ, measured as a function of temperature, had a high peak. Although the peak value of tan δ decreased with the increase of Pb content, it still remained at 0.7 for the specimen with 7000 Pb phr. Increased amounts of Pb content shifted the peak to the higher temperature side. The peak frequencies of tan δ of PNR-Pb compound sheets, estimated using the WLF equation, were 2200 Hz and 800 Hz at 5000 and 7000 Pb phrs, respectively. The sound transmission loss (TL) of the sheet was high, i. e., over 30 dB at 500 Hz for the specimen with 9000 Pb phr. The results indicated that TL obeys a mass law, while no coincidence effect appears in the audio frequency region. Furthermore, the extensional strength and Young's modulus were measured at room temperature. The PNR-Pb sheets can be expected to find applications as a material having high damping and good soundproofing.View full abstractDownload PDF (3145K) -
Osamu SANGEN, Hirohito YAMASAKI, Takuro KAMIMURA, Tohei YAMAMOTO, Luol ...1995 Volume 52 Issue 7 Pages 402-409
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPolyether-polyester block copolymer is a thermoplastic elastomer prepared by the polycondensation process; it is composed of polyether soft segments and polyester hard segments. Its outstanding elastic behavior is dependent on a favorable micro-heterophase separated structure. Accordingly, physical and mechanical properties of polyether-polyester elastomers are strongly governed by the extent of compatibility between the two segments. In molecular design, to properly build up a dispersed micro-heterophase structure, the polyether soft segments should be noncrystalliz-able. The present report deals with the synthesis of A-B-A and B-A-B type block copolyethers, each composed of PEG (A part) and PTMG (B part) segments. It also presents physical and mechanical properties of elastomers which include block copolyethers as the soft segment and poly (ethylene terephthalate) [T] as the hard segment. As a result of the incorporation of the block copolyether which has a low crystallizability into skeletal sequences of the block copolymer, a well mixed phase of hard and soft segments was observed, due to the improvement of compatibility of the soft phase with the hard phase. A good elastic fiber with high tensile strength and low Young's modulus could be prepared from a block copolymer.View full abstractDownload PDF (1479K) -
Hajime SERITA1995 Volume 52 Issue 7 Pages 410-414
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSGraft copolymers of chitosan were prepared by the reactions of chitosan with 3- (acrylamido) propyl trimethylammonium bromide. The flocculating ability for 5% kaolin suspension was investigated in relation to the structure of graft copolymers by measuring the sedimentation rate, the sedimentation volume, and the turbidity. The results obtained were as follows. 1) For every copolymer, the optimum flocculating ability was obtained in the concentration of 8-10 ppm and an isoelectric point was observed at the same copolymer dosage. 2) The flocculating ability of copolymer with increasing of graft chain length (F2) and graft ratio (Rg). 3) An isoelectric point was found in the vicinity of pH 4.5 and optimum flocculating ability was observed at the same pH. 4) Flocculating action was observed in the pH range 1-10, with the optimum flocculating action obtained in the pH range 2-6. 5) Copolymers obtained were more effective for flocculation than typical commercial flocculants such as Sumi-floc FC, PAS-A, and Himoloc Neo 600.View full abstractDownload PDF (834K) -
Satoshi TAKAMURA, Atsushi KAMEYAMA, Tadatomi NISHIKUBO1995 Volume 52 Issue 7 Pages 415-420
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSSeveral new photo-responsive polyamides containing norbornadiene (NBD) residue in the main chain were synthesized by the polycondensation of 2, 5-NBD-2, 3-dicarboxylic acid (NDC) with diisocyanates. From a polycondensation without catalyst in sulfolane at 80°C for 24 h, NBD polyamide having a number average molecular weight of (Mn) =11000 was obtained. In the reaction using various catalysts, however, it was found that the molecular weight of the resulting polymer did not increase. The reaction was investigated in various solvents without catalyst. The reaction proceeded very smoothly in dimethyl sulfoxide (DMSO) at room temperature to give the corresponding polymer with Mn=8000. When the reaction was carried out in DMSO at 100°C, the polymer having the highest molecular weight (Mn=20000) was obtained. Various NBD polyamides were also prepared by the reaction of NDC with certain diisocyanates under similar conditions.View full abstractDownload PDF (1038K) -
Ko AOYAGI, Yukio INOUE1995 Volume 52 Issue 7 Pages 421-426
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSWe studied the relationship between the depth profile of an anti-static agent containing sodium alkane sulfonate (SAS) and its anti-static effect in a polypropylene (PP) sheet to obtain a clear understanding of its anti-static mechanism. The SAS concentration at depths greater than the sub-micron level from the surface of a PP sheet as measured by EPMA (electron probe microanalysis) or FT-IR (Fourier transform infrared spectroscopy) increased linearly with the concentration of the anti-static agent, but showed no correlation with the surface resistivity. The SAS concentration, however, within a depth of about 2 nm from the surface of the PP sheet as measured by XPS (X-ray photoelectron spectroscopy) showed correlation with the surface resistivity. Furthermore, when the photoelectron intensity ratio of S to C within about 2 nm from the surface of the PP sheet reached saturation at about 0.05, the surface resistivity was about 109 Ω.View full abstractDownload PDF (4177K) -
Humidity-Electroconductive Properties of Plasma-Polymer Films Derived from Propargyl Alcohol MonomerKikuko YOSHIMURA, Keiichiro HOZUMI, Mikio SAWAI, Toshiaki TATSUTA, Osa ...1995 Volume 52 Issue 7 Pages 427-433
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA plastic plate on which a number of parallel electrodes were printed was coated with a plasma-polymer film derived from 2-propyn-1-ol (propargyl alcohol, PA) or 60% water-containing PA (PW). The electroconductive properties of the films exposed to ambient air at various levels of humidity were investigated. The electric current transported along the films was proportional to the voltage applied to the electrodes; the results were Ohmic irrespective of the given humidity or film thickness. The electric resistance of all the films had smaller values at high humidity than at low humidity. The resistance changed its value following increase of the humidity. The film having a thickness of 10000 Å seemed to have the best response characteristic for a wide range of humidity levels. In comparison with the film derived from PA, the other film from PW started to respond at somewhat lower humidity and showed steeper change of the resistance at high humidity. The film having a thickness of 10000 Å seemed to have the best response characteristic for a wide range of the humidity. Such a film might be applicable as a sensing device in a hygrometer. The response characteristic could be modified to some extent by using different compositions of the water-containing PA.View full abstractDownload PDF (1608K) -
Takeomi MIYAKO, Saburo AKIYAMA, P.M. THANG1995 Volume 52 Issue 7 Pages 434-439
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSMiscibility in the blends of various 1, 2-unit content PBD's with α-pinene, and β-pinene was investigated by differential scanning calorimetry and transmission light intensity measurements. The blends of PBD/β-pinene were immicible with any content of 1, 2-unit at all, while PBD/α-pinene blends were found to be miscible only at specified 1, 2-unit content of PBD. The results from transmission light intensity measurement, showed that PBD (1, 2-unit content: 30.1 wt%) /α-pinene had a lower critical solution temperature (LCST). The experimental cloud point curve was in good agreement with the binodal curve calculated by the Flory-Huggins expression. In the miscible PBD/α-pinene, pressure-sensitive-adhesion (PSA) properties were also estimated by DMA and PSA tests (180°peel strength, holding power, and probe tack). Good results for the adhesive properties were interpreted in terms of the dynamic mechanical behavior of the blends.View full abstractDownload PDF (974K) -
Arimitsu USUKI, Masaya KAWASUMI, Yoshitsugu KOJIMA, Akane OKADA, Toshi ...1995 Volume 52 Issue 7 Pages 440-444
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSIn this report, we added hexamethylene diamine (HMDA) to nylon 6-clay hybrid (NCH), in which some silicate layers were laminated and these laminated layers were dispersed in the nylon 6 matrix. The diamine-modified NCH had sufficient elongation and impact strength. However, the strength and modulus slightly decreased. The silicate layers were pillared by diammonium ion of the diamine in the diamine-modified NCH. It is considered that the decrease of mechanical properties results in a lowering of the surface area between the silicate layers and nylon 6.View full abstractDownload PDF (1799K) -
Wataru MIZUNO, Makoto KAWAGOE, Jianhui QUI, Mikio MORITA1995 Volume 52 Issue 7 Pages 445-451
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSMechanical properties and variations in viscoelastic properties during fatigue of injection-molded polypropylene were investigated by means of fatigue and tensile tests. Fatigue fracture and morphology of the specimen were investigated by microscope, and infrared spectroscopy studies. Fatigue fracture occurred after cracking in spherulitic core region. The fatigue life time decreased with increase in stress amplitude. For high stress amplitude, the growth of cracks and the softening of the specimen occurred locally. The crystallinity of the specimen after fatigue test was higher than that before the test because of heating during the fatigue process. The crystallinity increased with increase in the fatigue lifetime. Fracture of tensile test occurred after growth of a wide crack in the spherulitic core region.View full abstractDownload PDF (6893K) -
Sadao HAYASHI, Takuto SEO, Tomoko WATANABE, Toshihiro HIRAI1995 Volume 52 Issue 7 Pages 452-460
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSOptics between two convex lens arrays (LA) with a relatively large aperture of 2.30 mm made from poly (methyl methacrylate) has been investigated. The inverted image focused by the lens at the center in the first LA appeared in the middle of the lens, but those by other lenses shifted to the upper and lower sides or to the right and left sides within each lens, as lenses went away from the middle to the four sides on the LA. When the second LA was superposed on the first LA, an upright image was formed by shining lenses in the second LA. If the second LA was rotated, the image in the second LA was leaned toward the rotational direction with decreasing size. The size of the upright image was theoretically the same as that of an object. This was experimentally proved. The mechanism of the image formation in the second LA was based on the principle that the focal point of lenses in the second LA overlaps on the focal plane of lenses in the first LA, and the focal point picks up the inverted image of the first LA by Moiré fringes between the pitch of inverted images in the first LA and the pitch of lenses in the second LA. The optics between two LAs was found to have a potential application to a new image sensor.View full abstractDownload PDF (11448K) -
Kohei KUGO, Eiji NAKANISHI, Mitsuru HASEGAWA, Jun NISHINO1995 Volume 52 Issue 7 Pages 461-464
Published: July 25, 1995
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe pH response for the secondary structure of amphoteric copolypeptide hydrogels was investigated through in situ monitoring using a Fourier transform IR microscope equipped with an attenuated total reflectance objective. Copolypeptides consisting of L-glutamic acid, L-leucine, and L-lysine were used as amphoteric hydroaels. The hydrogels were found to exist mainly in the α-helical conformation over the whole pH range studied. Furthermore, the peak position of amide II of the hydrogels shifted depending on the composition and pH, that is, the effective charge. This shift implies that the intermolecular interactions involving the amino groups of α-helical molecules were weakened through the swelling of amphoteric hydrogels due to the dissociation of their side chains.View full abstractDownload PDF (608K)
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