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Predecessor
Volume 58, Issue 2
Displaying 1-6 of 6 articles from this issue
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Wataru MIZUNO, Yoshiko MAEDA, Kanako KOZIMA, Tomomi TAKAMICHI, Kanji M ...2001 Volume 58 Issue 2 Pages 59-65
Published: February 25, 2001
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSBiodegradation behavior of test pieces of some biodegradable polymers formed by injection molding was investigated in soil, aqueous environments, and an activated sludge. The manner of the biodegradation depended on the composition of materials. With regard to the tests in soil and aqueous environments in the field, the degradation progressed during spring and fall. In an activated sludge of a sewage treatment plant, Biopol and Mater-Bi were degraded. The extent of the degradation of Biopol was influenced by the density of microbes. The degradation of Biopol was facilitated in an aeration tank, in which the microbe density was high. It was estimated that about 50 wt% of the biodegradable polymers was degraded in one year in the activated sludge. Waste treatment of polymers in a sewage treatment plant would be one of the effective methods, provided the safety of the treatment is confirmed.View full abstractDownload PDF (3145K) -
Naruhiko MASHITA, Yoshihide FUKAHORI2001 Volume 58 Issue 2 Pages 66-72
Published: February 25, 2001
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSWe report general features of mechanical properties of the physical gel of semi-crystalline hydrogenated styrene-butadiene rubber and straight asphalt having clearly observed μm-ordered bicontinuous network phase separation. The gel shows rubber-like stress-strain relationship that results from the polymer network phase; on the other hand, the gel exhibits large Tan δ at small through large deformations, which is originated in the asphalt phase. The semi-crystalline polymer network structure keeps control of flow and bleeds of asphalt. It is, thus, a novel material of which bicontinuous phase structures share in the functions of keeping its form and exhibiting large damping.View full abstractDownload PDF (2217K) -
Akira MATSUURA, Takanori HAYASHI, Masakazu FURUTA, Toshio HAYASHI2001 Volume 58 Issue 2 Pages 73-77
Published: February 25, 2001
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSModification of microbial transglutaminase (MTG) with poly (ethyleneglycol) -phenylcarbonate (PEG) was carried out to stabilize the enzyme and preserve its activity while retaining its solubility in water. The modification between MTG and PEG was based on covalent bonding. The relative activity (RA) and stability were evaluated on the modified MTG (PEG-MTG). High RA was found for PEG-MTG toward the formation of hydroxamic acid from N-carbobenzoxy-L-glutaminyl-glycine (COG) and hydroxyl-amine. The thermal and storage stabilities of PEG-MTG were higher than that of free MTG in spite of RA values being their slightly lower than that of free MTG. PEG-MTG had the same pH optimum as free MTG, but the pH profile of PEG-MTG was slightly broad. PEG-MTG displayed higher stability than free MTG at high pH region.View full abstractDownload PDF (1042K) -
Toshio OGAWA, Sumio OWARI, Satoshi OSAWA2001 Volume 58 Issue 2 Pages 78-85
Published: February 25, 2001
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSAn outdoor exposure test was carried out for polyvinyl chloride film; the tensile strength at break, elastic modulus, and elongation at break of the sample were determined every month. Then an equation was derived using the method of multiple regression analysis between mechanical properties and meteorological data, i. e., temperature, precipitation, hour of daylight, and quantity of ultraviolet rays. The equations thus obtained were applied to the experimental results obtained under different conditions. The mechanical properties were predictable only from the meteorological data, when once the correlation between mechanical properties and meteorological conditions was established.View full abstractDownload PDF (1281K) -
Takao KIMURA, Hiroyuki MIYATA, Asako TANAKA, Seiji NISHIKAWA2001 Volume 58 Issue 2 Pages 86-91
Published: February 25, 2001
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSCopolycondensations of (2R*, 4S* ) -4-chloroformy1-2-chloroforrnylmethy1-2, 4-dimethy1-4-butanolide (BC) and 4, 6-dichloroformyl-2H-pyran-2-one (PC) with 1, 6-hexanediamine were carried out under the following feed molar ratios, BC: PC=100: 0, 75: 25, 50: 50, 25: 75, and 0: 100. The incorporation effect of the 2-pyrone skeleton into a polyamide containing a five-membered lactone unit in main chain was investigated with regard to solubility, film molding, hydrophilicity, and thermal properties. Solubility and film forming property of the polyamide lowered by the incorporation of PC. However, the water content of the 50: 50-copolyamide was higher than that of either homopolyamide. The glass transition temperature of a series of polyamides rose with an increase in the incorporation ratio of PC. Furthermore, the polyamide including PC showed a weight loss which was accompanied by exothermic reaction within 200-250°C, and the weight loss increased with the incorporation ratio of PC.View full abstractDownload PDF (1208K) -
Toshio AZECHI, Masanori HANSAKA, Naoto MIFUNE, Riichiro OHARA2001 Volume 58 Issue 2 Pages 92-98
Published: February 25, 2001
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSBecause the need of labor-saving in train maintenance continues to increase, it has become essential to evaluate the endurance and long-time applicability of air springs, which are very important components to control train vibration. Endurance tests of air springs revealed that their rubber bellows degraded by oxygen at the initial stage of usage. As stresses are loaded repeatedly, however, molecular chains are partly cut off, and consequently the tensile strength decreases. It is also found that the degradation of air spring rubber bellows is apparently different at different locations and in different directions in the air spring because it is strongly influenced by the vibration mode, for example, the center part of rubber bellows degrades to some extent because it is subject to train vibration, while the upper and lower parts of rubber bellows don't degrade so much because they are isolated from strong vibration.View full abstractDownload PDF (2207K)
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