All issues
Predecessor
Volume 61, Issue 9
Displaying 1-5 of 5 articles from this issue
- |<
- <
- 1
- >
- >|
-
Satoshi OSAWA, Kaoru KABEYA, Takahiro HORII, Toshio OGAWA2004 Volume 61 Issue 9 Pages 469-473
Published: September 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSEffects of sunshine duration and of precipitation on the degradation of poly (ε-caprolactone) (PCL) and poly (butylensuccinate/adipate) (PBSA) have been investigated by applying multiple regression analysis. The analyses showed that the tensile strength of PCL and PBSA exposed to outdoor conditions can be described by kW and k′U, where k and k′are rate constants of hydrolysis and photo-degradation, respectively. W the rain-fall during a day, and U the sunshine duration (ultraviolet). The contributions of k' U (photo-degradation) to the reduction of tensile strength for PCL and PBSA were 2 times and 5 times higher than those of kW (hydrolysis), respectively. There was no effect of microorganism on the degradation of PCL and PBSA in the outdoor tests. Hydrolysis and photo-degradation tests for PCL and PBSA were also carried out at different temperatures in the laboratory. The activation energies of hydrolysis were higher than those of photo-degradation for PCL and PBSA. The results suggested that the degradation caused by solar radiation was much prominent than that by precipitation for both PCL and PBSA.View full abstractDownload PDF (1384K) -
Satoru AMOU, Shinji YAMADA, Akira NAGAI, Takao MIWA, Masao TOMOI2004 Volume 61 Issue 9 Pages 474-482
Published: September 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSBifunctional Styryl Resins Styryl resins, Bis (vinylphenyl) methane (BVPM), 1, 2-Bis (vinylphenyl) ethane (BVPE), and 1, 6-Bis (vinylphenyl) hexane (BVPH) could be cured without curing agents at relatively low temperatures (-180°C) in a nitrogen atmosphere. The cured resins showed low dielectric constant (ε′=2.4-2.5 at 10 GHz) and low dielectric loss tangent (tan δ=0.0012-0.0036 at 10 GHz) and had excellent thermal resistance. The 5 wt% weight-loss temperature was beyond 440°C in a nitrogen atmosphere. Poly (phenylene ether) (PPE) was used as a modifier to improve the toughness of cured BVPE (CBVPE) resin. When using 30 wt% of the modifier, the tensile strength and elongation of the modified CBVPE resin were 75 MPa and 26%, respectively. The CBVPE resin modified with PPE also showed excellent dielectric properties (ε′=2.45 at 10 GHz, tan δ=0.0015 at 10 GHz).View full abstractDownload PDF (4649K) -
Hiroaki KOUZAI2004 Volume 61 Issue 9 Pages 483-488
Published: September 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSHydrogen transfer polymerization of acrylamide (AAm), methacrylamide (MAAm), crotoramide (CAm), and tiglinamide (TAm) catalyzed by sodium (Na) -anthracene, -diphenyl, -pyrene, -phenanthrene, -o-terphenyl, -m-terphenyl, and -p-terphenyl was studied under various conditions. The initiation reaction of MAAm, CAm, and TAm polymerization was proton abstraction from the amide end group. The optimum conditions were as follows: when a 0.7-1.4mol/L solution of AAm containing 0.04mol/L Na-diphenyl was reacted under dry nitrogen at 100-140°C for 3 hr in toluene, polymer with a viscosity number of 0.48-0.52dL/g was obtained in 92-97% yield.View full abstractDownload PDF (1128K) -
Takashi MASUKO2004 Volume 61 Issue 9 Pages 489-496
Published: September 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSComposite films composed of a polyimide, an epoxy resin, and copper fillers were prepared. Effects of the filler shape and size on the dynamic mechanical properties and fracture strength of the composite films were studied. The composite films were filled with flaky or spherical copper filler. Both of these fillers were sorted into two groups having different mean sizes of 1μm and 4μm. The dynamic mechanical properties were analyzed in the tensile mode. The fracture strength was measured by peeling the film in the thickness direction. The film filled with the finer flaky filler had the higher storage modulus; the dispersed peak position shifted to the higher temperature. On the other hand, the film filled with the finer spherical filler had the higher fracture strength. In this paper are discussed the relationships between these mechanical properties and the filler orientation in the film, the interfacial structure between filler and polymer, and the influences of the filler shape and size.View full abstractDownload PDF (8416K) -
Asuka SHIMODA, Takashi MITSUMATA, Hiroaki KOUZAI2004 Volume 61 Issue 9 Pages 497-499
Published: September 25, 2004
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSLiquid crystalline poly (phosphate ester) s were synthesized by polycondensation of methyl posphoro-dichloridate with 4, 4′-Bis [co- (2-hydroxyethoxy) ethoxy] -biphenyl (BHEBm) and 4, 4′-Bis [w- (2-hydroxyethoxy) -ethoxy] benzylideneaniline (BHEBAm). The polymers were obtained with high yield, i. e., 73-82%. The intrinsic viscosities were in the range of 0.18-0.23 dL/g. The liquid crystallinity of these polymers was studied by differential scanning calorimetry, polarizing optical photomicrograph, and X-ray diffractometry, and it was found that most of the polymers had enantiotropic liquid crystallinity having smectic phase.View full abstractDownload PDF (2491K)
- |<
- <
- 1
- >
- >|