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Predecessor
Volume 61, Issue 11
Displaying 1-5 of 5 articles from this issue
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Takashi SAEKI, Takayuki TSUKEGI, Hideto TSUJI, Hiroyuki DAIMON, Koichi ...2004 Volume 61 Issue 11 Pages 561-566
Published: November 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPoly (L-lactic acid) (PLLA) was readily depolymerized by hydrolysis under hydrothermal conditions in the absence of catalysts. The optimum condition for depolymerization of PLLA was found to be 220°C and 20 min. Under this condition, the recovery of L-lactic acid was more than 95% without loss of optical purity. At a higher temperature (260-300°C), the optical purity decreased with increasing temperature, and a racemic mixture was formed at 300°C. Based on these results, the method was found to be promising for recycling PLLA by converting it to its monomer, L-lactic acid.View full abstractDownload PDF (3945K) -
Yoshihisa TAJIMA, Hiroshi OHNUMA2004 Volume 61 Issue 11 Pages 567-572
Published: November 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe creep characteristics of polyacetals, copolymers and homopolymers with high/low molecular weights were investigated under various loads at 80 degrees C. From the slopes of load vs. log (rupture time) lines, the activation volume, υc, derived from Zhurkov equation was estimated. It was found the value of υc becomes larger with higher molecular weight and that the υc of copolymer is larger than that of homopolymer. From SEM observation and the comparison with υc and the activation volume, υy, of tensile yielding process based on Eyring's equation, we concluded that the creep behavior of the polyacetal should result from the dominant ductile rupture.View full abstractDownload PDF (5438K) -
Shigeki HIKASA, Kazuya NAGATA, Kazuhiko MAEKAWA, Mototsugu YOSIHARA, Y ...2004 Volume 61 Issue 11 Pages 573-577
Published: November 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe influence of the addition of ethylene-b-acrylate copolymer (PE-diblock) on the mechanical properties of polypropylene filled with CaCO3 composite was investigated. CaCO3 particles were more easily dispersed in PP matrix by addition of PE-diblock, polypropylene-b-acrylate copolymer (PP-diblock), and maleic acid modified PP (MAh-PP). Addition of these polar unit-induced polymers improved the adhesion between CaCO3 particles and PP matrices. The Izod impact strength of PP loading with 50wt% of CaCO3 rapidly increased with increasing of addition of PE-diblock to 5wt%. On the other hand, the lzod impact strength of PP/CaCO3 composites gradually decreased with increasing of addition of PP-diblock and MAh-PP. The modulus of PP loading with 50wt% of CaCO3 decreased from 2400 MPa to 1500 MPa by addition of PE-diblock to 5wt%. On the other hand, the modulus of PP/CaCO3 composites remained almost constant during addition of PP-diblock and MAh-PP. These results suggest that some CaCO3 particles, with which elastomer-like PE-diblock polymers are coated, exist in the EPR domain of matrix PP.View full abstractDownload PDF (3806K) -
Kouki JYODOI, Masashi YAMASHITA, Kotaro KURAMOTO, Kouhei TANEMURA, Shu ...2004 Volume 61 Issue 11 Pages 578-582
Published: November 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA hydrocarbon-type anion exchange membrane was soaked in aqueous sodium tetrachloroaurate (III) solution, and the adsorbed AuCl4- anion complex was reduced by sodium sulfite. With four sequential adsorption/reduction cycles, a fractal-like gold structure was obtained. After the counter ions in the membrane were replaced with various carboxylate ions, a voltage was applied to the membrane, and the current flowing through the membrane and the displacement were measured. The results were discussed in terms of the size of the carboxylate ion and the channel size in the membrane.View full abstractDownload PDF (3226K) -
Yoshikazu HOSHIMURA, Kengo TSUCHIDA2004 Volume 61 Issue 11 Pages 583-586
Published: November 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe spatial charge distribution of polyethylene resins (PE) with vapor grown carbon fibers (VGCF) was measured with the pulsed electro-acoustic (PEA) method. A DC voltage of 2 kV was applied to each PE with VGCF of 0.1 phr and to each PE with VGCF of 0.01 phr for ten minutes, the paths were short-circuited afterwards. The results showed that the charge density increased more than for PE without VGCF. The charge density of PE with VGCF of 0.1phr was the same as PE with VGCF of 0.01 phr when the voltage was applied to them. However, the positive charge of PE with VGCF of 0.1phr increased after it was short-circuited. Also, the charge density of a roll film of PE with VGCF increased more than that of a film of PE without VGCF.View full abstractDownload PDF (944K)
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