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Volume 60, Issue 7
Displaying 1-9 of 9 articles from this issue
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Masao SUZUKI2003 Volume 60 Issue 7 Pages 321-328
Published: July 25, 2003
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe gelation and network structures of an epoxy/silica hybrid system containing epoxy, dicyandiamide (DICY), and alchoxysilane were studied. The relationship between their network structures and gelation points can be described by a simple model. If the group number of used epoxys and the content of alchoxy silane were given, we would obtain the gelation time. The gelation time of the epoxy/silica hybrid system that contains γ-glycidoxypropyltrimethoxysilane (GPTMS) and phenyltriethoxysilane (PTES) was extended. Results agreed with the predicted ones.View full abstractDownload PDF (1540K) -
Yasuyuki MASUBUCHI, Katuya MAEYAMA, Noriyuki YONEZAWA, Tokio HAGIWARA2003 Volume 60 Issue 7 Pages 329-334
Published: July 25, 2003
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSEffect of an acid anhydride as an additive on the polymerization of Tetrahydrofuran (THF) initiated by the reaction of hexafluoropropylene oxide (HFPO) with THF was investigated. In the absence of additives, only a low polymer was obtained (Mn=1.1×103). In this polymerization fluoride anions generated through the initiation reaction by the ring-opening reaction of HFPO caused by the nucleophilic attack of THF terminates the polymerization at an early stage of the propagation (telomerization). On the other hand, when a 5-membered cyclic acid anhydride such as maleic anhydride was used as an additive, the polymer obtained had a high molecular weight (Mn=8.4×104) probably because that termination may be suppressed by the 5-membered cyclic acid anhydride. The end group of the polymer could be easily modified by esterification. The thermal decomposition temperature of this polymer was 211.1 °C.View full abstractDownload PDF (1130K) -
Toshiya ISHII, Tadashi HONGO, Machiko MORITA, Toshio OGAWA2003 Volume 60 Issue 7 Pages 335-346
Published: July 25, 2003
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe interfaces between extrusion-coated low-density polyethylene (LDPE) and boehmite-treated aluminum were analyzed. When aluminum was treated with boiling water, hydrated aluminum (boehmite) was produced on the surface. The adhesion strength of hydrated aluminum with LDPE increased with the progress of boiling times. In order for one to discuss adhesion mechanisms between LDPE and boehmite, analysis of interfaces between LDPE and boehmite is important. However, peeled surfaces for LDPE side experience plastic deformation and peeled surfaces for boehmite side experience interfacial failure between boehmite and aluminum substrate. In this study, the peel tests were carried out on various laminates that had been immersed in water for 3 days. The surface structures of boehmite and peeled surface were analyzed by ultra high resolution Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy (XPS). During interfacial failure between LDPE and boehmite, peeled surface for LDPE side does not show plastic deformation and peeled surface for boehmite does not show interfacial failure between boehmite and aluminum substrate. It was suggested that adhesion between LDPE and boehmite is hydrogen bonding. And the adhesive strength depended on the depth that LDPE had penetrated onto boehmite, on the angle of LDPE surface topograph at interface and on the surface area of LDPE at interface. Adhesive strength between LDPE and boehmite increased as these values increased.View full abstractDownload PDF (6702K) -
Tokio KIKUCHI, Tatsuhiro TAKAHASHI, Kiyohito KOYAMA2003 Volume 60 Issue 7 Pages 347-353
Published: July 25, 2003
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe thermal conductivity of polymers in the solid and molten phases, as functions of temperature and pressure, is an essential parameter to permit simulation of polymer processing by computer-aided engineering (CAE). A key factor for the thermal conductivity when used in CAE is the Bridgman parameter (g) as a function of temperature. This is experimentally examined for high density polyethylene (HDPE) and low density polyethylene (LDPE) in this paper. The thermal conductivity results under pressure could be well described by the Eiermann equation. Firstly, the product of the Bridgman parameter (g) and the compressibility (b) as a function of temperature was calculated by fitting the experimental values with the Eiermann equation. Secondly, the compressibility (b) as a function of temperature was estimated from the slope, in the plot of specific volume as a function of pressure. Finally, the Bridgman parameter (g) as a function of temperature was obtained from the previous figure. The Bridgman parameters from the experiments are discussed by comparing them with those from Eiermann's theoretical model.View full abstractDownload PDF (1386K) -
Toshihiro FUJII, Nozomi IKEZOE2003 Volume 60 Issue 7 Pages 354-358
Published: July 25, 2003
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA convenient extraction procedure (called Shindai method) was applied for protein separation from sheep wool and wool yarn. The extraction protein amount obtained by Shindai method was about 1.5 times more than that obtained by the conventional method. Obtained proteins are mainly composed of hard α-keratins and matrix proteins. No significant hydrolysis and no differences of the protein components between sheep wool and wool yarn samples were observed. We found the presence of serine phosphorylation in α-keratins and matrix proteins, and that of threonine and tyrosine phosphorylation in α-keratins; such processed would indicate the presence of posttranslational modifications in wool proteins. A novel procedure to preparae protein-coated fibers was developed. About 5mg of protein was maximally bound to each g of the gauze (cotton cloth). Scanning electron microscopy shows that the surfaces of the fibers of the gauze are composed of filamentous structures of α-keratins with a diameter of 1-21. μm.View full abstractDownload PDF (3663K) -
Study of the Complex between DNA and DEAE-DextranYasuhiko ONISHI, Yasuo KIKUCHI2003 Volume 60 Issue 7 Pages 359-364
Published: July 25, 2003
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSDEAE-dextran is an important substance for mediating transfection of human macrophages. The transfection of human macrophages is accomplished via the complexation between DNA and DEAE-dextran. Such complexes were thus synthesized using DNA from a salmon spermary under various conditions including reaction time and pH, and analyzed by IR absorption spectroscopy and DSC. From the relation between the yield, pH, and reaction time, the optimum pH was in the range 7-10. The relation between the weight ratio of DNA/DEAE-dextran in the complex, pH, and reaction time indicated the ratio to be 1/1 in the pH range 6-9. The IR absorption spectra and DSC curves confirmed that the complexes were formed by the coulomb force between a single and tandem DEAE-group in DEAE-dextran and phosphoric acid in DNA.View full abstractDownload PDF (3728K) -
Toshiya UOZUMI, Yasunori OUMI, Tsuneji SANO2003 Volume 60 Issue 7 Pages 365-368
Published: July 25, 2003
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPolymerization of 1, 5-hexadiene with Ziegler-Natta or Metallocene catalysts affords poly (methylene-1, 3-cyclopentane), which predominately consists of cis- and trans-cyclopentane rings. The molar ratio and distribution of two rings in the polymer are strongly dependent upon the catalyst used. In this study, we conducted the polymerization of 1, 5-hexadiene with (CH3) 2Si (Fluorenyl) 2ZrCl2-MAO catalyst, which shows the high performance for the syntheses of high-molecular atactic polypropylene as well as poly (ethylene-alt-α-olefin). A highly crystalline poly (methylene-1, 3-cyclopentane) is produced in good yield. The 13C NMR analysis also showed that cis- and transcyclopentane rings were arranged alternatively in the polymer chain.View full abstractDownload PDF (644K) -
Naruhiko MASHITA, Yuichiro WAKANA, Yasuo HORIKAWA2003 Volume 60 Issue 7 Pages 369-372
Published: July 25, 2003
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA novel non-aqueous physical gel made of polypropylene, a comb-like polymer, and a plasticizer was examined in terms of morphology, thermal and mechanical properties. Observed directly with an optical microscope, the gels consisted of three-dimensional continuous polymer networks whose diameter was a few tens of micrometers. A gel system exhibited tan δ=0.58 (20°C, 10Hz, 10% strain in torsion) even though its glass transition temperature was -55°C. Melting temperature of the physical gel was around 136°C, and thus, the system can be applied to a soft damping material for wide service temperature ranges.View full abstractDownload PDF (1327K) -
Naruhiko MASHITA, Tadashi MINAMIKAWA, Kentaro UESUGI, Hiroshi JINNAI2003 Volume 60 Issue 7 Pages 373-376
Published: July 25, 2003
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA phase structure of a non-aqueous physical gel was speculated to be somewhat different from what is typically observed in binary liquid mixtures, e. g. the island-in-sea structure or bicontinuous structure. This is primarily because the conventional microscopy, scanning electron microscopy, and even laser scanning confocal microscopy offer structural information only at (or near) the surface and thus limited structural information can be obtained. High resolution X-ray computer tomography installed at SPring-8 was used to obtain threedimensional (3D) structure of the gel in non-destructive way. It was found for the first time that oil-containing cells were connected to make continuous oil-rich domains in the 3 D space (“microcellular porous structure”). This observation confirms the speculative model proposed in the previous study and also implies significance of dynamical asymmetry of the two components, i. e. oil and crystalline elastomer, during the gel formation processes.View full abstractDownload PDF (3311K)
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