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Volume 42, Issue 7
Displaying 1-8 of 8 articles from this issue
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Nobuhide YAHIRO, Shigekazu ITO1985 Volume 42 Issue 7 Pages 427-436
Published: July 25, 1985
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe ring opening polymerization of variou (S) -N-alkyl-2-isobutylethylenimines catalyzed by boron trifluoride etherate gave a viscous or powder polymer. Optical rotation, optical rotatory dispersion and circular dichroism in cyclohexane indicated that the copolymers existed in different structures from the corresponding homopolymers. Asymmetric reduction of acetophenone by optically active hydride reagents prepared from lithium aluminum hydride and the homopolymers or the copolymers, yielded optically active 1-phenylethanol. It was clarified that the conformation of optically active polyethylenimines played a prerequisite role for the asymmetric reduction.View full abstractDownload PDF (1603K) -
Kazuta MITSUISHI, Soji KOMADA, Hitoshi KAWASAKI1985 Volume 42 Issue 7 Pages 437-442
Published: July 25, 1985
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSAn investigation has been made of the relation between void volume and tensile Young's moduli of the oriented polypropylene filled with calcium carbonate. Filler volume fractions are from 0.016 to 0.21. Filler particle sizes are 1.0, 4.5 and 30μm. Draw ratios of polypropylene composites are 4, 6, and 8. The void volume increases with increasing the filler volume fraction, filler size, and draw ratio. The young's modulus of oriented composite increases with increasing the draw ratio, but decreases with increasing the filler volume fraction and filler size. The relative modulus Ecd/ERd (where Ecd and ERd are the modulus of oriented composite and the modulus of oriented polymer matrix, respectively) can reasonably be explained by the void volume alone, irrespective of the filler size of filler volume fraction.View full abstractDownload PDF (1359K) -
Shunichi NUMATA, Noriyuki KINJO1985 Volume 42 Issue 7 Pages 443-451
Published: July 25, 1985
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe rates and activation energies for decomposition of various polyimides in nitrogen and air are determined under the isothermal conditions. Decomposition rates in nitrogen are smaller than those in air, and activation energies for decomposition in nitrogen are larger than those in air. In the decomposition in nitrogen, a polyimide with a higher decomposition temperature shows a larger activation energy. A linear relationship exists between the bond dissociation energy for the bond with the smallest dissociation energy in polyimide chain and the decomposition temperature in nitrogen and air for various aromatic polyimides. In the decomposition in nitrogen, the activation energies are close to the smallest value in the bond dissociation energies, and the activation energy linearly increases with the bond dissociation energy. This indicates that the rate-determining process of decomposition in nitrogen is the radical cleavage at the bond which has the smallest bond dissociation energy. In the case of decomposition in air, however, no relationship exists between them, indicating that the rate-determining process is not the radical cleavage.View full abstractDownload PDF (1318K) -
Ken-ichi NAKAZATO, Kiichi SUZUKI1985 Volume 42 Issue 7 Pages 453-460
Published: July 25, 1985
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSN -Hydroxymethylacrylamide and N, N′-methylenebisacrylamide were suspended in petroleum hydrocarbon and polymerized to give spherical hydrophilic porous gels by the use of water as a diluent. Exclusion limit of gels increased with increasing composition of crosslinking agent and took nearly constant values 16000 above around 8 mol% crosslinking agent. However, a gel of macroreticular structure was obtained at 32.0 mol% by employing a mixture of ethanol and water as a diluent and increasing of composition of crosslinking agent: the exclusion limit of the gel was 316000 and its mean pore diameter was 53.7±4.1 Å in swollen state. In polyacrylamide gels prepared from N-hyOroxymethylacrylamide, acrylamide, and the crosslinking agent (7.5 mol%), by the use of water as a diluent, degree of swelling (wet-ml/dry-ml), amount of water regain (g/dry-g), exclusion limit, spcific surface area (mm2/g), mean pore diameter, and C-potential of gels respectively increased with increasing mole fraction of acrylamide to N-hydroxymethylacrylamide plus acrylamide.View full abstractDownload PDF (1506K) -
Toru WADA, Tomoko MATSUI, Shigeyuki TANAKA1985 Volume 42 Issue 7 Pages 461-465
Published: July 25, 1985
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSAnalytical method was examined for the secondary structure of adsorbed bovine serum albumin on artificial antithrombus materials. Treatments prior to analysis were as follows. (1) phosphate buffer solution (pH 7.4) and no heating. (2) 0.9% NaCl/H2O (pH 5.2), heating for 90 min. at 90°C. (3) phosphate buffer solution (pH 7.4), heating for 90 min. at 90°C. After heating, the gelation occurred in the case of (2), but no change was observed in the case of (3). The amount of α-helix in (3) decreased about 35% relative to the value in (1) (by CD spectrometry). The difference in albumin spectra (KBr tablet method) between the condition of (2) and (1) was clearly recognized, but the spectra of (3) and (1) were nearly same. The increasing amount of β-structure in (2) was estimated by the subtraction spectrum ((2) minus (1)). Hydrogendeuterium exchange reaction rates were measured for the samples of (1) and (3) (R1, R3). The datum (R3> R1) indicated that albumin in (3) was denatured. Examination of H-D exchange reaction rate has been useful to estimate secondary structure of adsorbed protein on material surface that is not able to examine by transmission method.View full abstractDownload PDF (778K) -
Yoshiyuki KONDO, Masatoshi NAOI, Katsuhiro KOYAMA, Toshihiro FUJII, Ko ...1985 Volume 42 Issue 7 Pages 467-471
Published: July 25, 1985
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe conformational change of porcine brain calmodulin (CaM) with several surfactants has been investigated by using fluorescence spectra and circular dichroism (CD) measurements. Nonionic surfactants such as Tween 20, Tween 40, Tween 80, and Triton X100 had little effect on the conformation of CaM. Drastic conformational change of CaM was observed when anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) were added. Addition of 1 mM SDS increased α-helical content of CaM both in the presence and the absence of Ca2+, and the α-helical content was 42% in the presence of Ca2+. When SDBS was added, the α-helical content of CaM decreased with increasing the surfactant concentration. At high SDBS concentration (12 mM) the CD spectrum was typical of a random coil both in the presence of Ca2+ and in its absence. Addition of the cationic benzalkonium chloride enhanced the breaking of an ordered conformation with a weak denaturation. These facts were supported by the results of fluorescence spectroscopy.View full abstractDownload PDF (877K) -
Kazuo KAMAGATA, Shuuji YOSHIDA, Takashi MIZUI1985 Volume 42 Issue 7 Pages 473-480
Published: July 25, 1985
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSA simultaneously cured compound of epoxide resin and 2, 4-diamino-6-vinyl-s-triazine was prepared from the anion polymerization of epoxide resin with imidazole and radical polymerization of 2, 4-diamino-6-vinyl-s-triazine.
The curing reaction of epoxide resin and 2, 4-diamino-6-vinyl-s-triazine in the presence of imidazole was faster than that in its absence.
The glass transition temperature of this compound was higher than that of the epoxide resin cured with imidazole in the presence of poly (vinyl-2, 4-diamino-s-triazine) prepared using azobisisobytyronitrile in water or water-ethyl alcohol solution of epoxide resin at 80°C or 2, 4-diamino-6-ethyl-s-triazine.
In a simultaneously cured compound, the formation of the phase containing poly (vinyl-2, 4-diamino-s-triazine) in the cured epoxide resin was estimated from the results of DTA, TBA and IR.
The flexual strength, volume resistivity, dielectric constant and the dielectric loss of the simultaneously cured compound were superior to those of the cured epoxide resin polymerized with imidazole, especially in the high temperature region.
Simultaneously cured compounds are better as materials of electric insulation than the epoxide resin cured with imidazole.View full abstractDownload PDF (1132K) -
Norihiko MINOURA, Sei-ichi AIBA, Yukihiko FUJIWARA, Tsutomu NAKAGAWA1985 Volume 42 Issue 7 Pages 481-483
Published: July 25, 1985
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSWater vapor permeability, rigidity, and mechanical properties of threekinds of poly (α-amino acid) membranes with lower percentages of cell attachment: oxidized poly (L-methionine), copoly (L-leucine, γ-benzyl-L-glutarnate), and copoly (L-leucine, Ne-carbobenzoxy-L-lysine) were evaluated as wound-covering materials. The water vapor permeability was sufficient for wound-covering materials, but the mechanical property was not sufficient. The oxidized poly (L-methionine) looks most promising.View full abstractDownload PDF (593K)
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