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Volume 54, Issue 2
Displaying 1-8 of 8 articles from this issue
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Shigeki TAKAYAMA, Tomoyuki ISHIKAWA, Kunihiko TAKEDA1997 Volume 54 Issue 2 Pages 61-68
Published: February 25, 1997
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSFatigue and structural deformation of engineering plastics such as polyphenylene-ether (PPE), PPE/polystyrene (PS) alloy, polycarbonate (PC), and polyamide 66 (PA 66) have been examined by the continuous viscoelastic method. The heat generation, energy of loss modulus, and mutual relation have been also measured. Fatigue life depended upon the contents of PPE as well as the experimental conditions such as repeated displacement to the specimens. Percent of work that appears as heat (PWAH) by loss modulus were about 40-60%. The PWAH increased with an increase in entanglement density of polymer. The decreases of molecular weight of the specimens were large enough to reduce the mechanical strength of the polymers. However, the ratios of the energy consumed for cleavage of the polymer chains to the whole energy during the fatigue tests were so small that they were thought to contribute to reduce the mechanical strength of the specimens. It was possible that the defects in the specimen which were generated newly during the fatigue tests did not play an important role for determining the fatigue lives.View full abstractDownload PDF (3955K) -
Yasumi KOINUMA, Yoshishige MURATA, Takayuki OTSU, Yusaku TAKITA1997 Volume 54 Issue 2 Pages 69-78
Published: February 25, 1997
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSDiisopropyl fumarate (DiPF), a monomer with bulky ester substituents, was copolymerized with some kinds of comonomers, styrene (St), vinyl acetate (VAc), methyl methacrylate (MMA), methacrylic acid (MAA), acrylonitrile (AN), isobutylene (IB), 1, 3-butadiene (BD), and vinyl chloride (VC), with a radical initiator at 60°C. DiPF underwent copolymerizations with St, VAc, AN (r1=0.197, r2=16.13; reactivity ratios for copolymerization of DiPF (M1)), IB (r1=0.418, r2=0.0), BD (r1=0.142, r2=0.895), and VC (r1=0.488, r2=0.292), but it showed little reactivity to MMA and MAA. In the copolymerizations of St, VAc, and VC containing less than 5mol% of DiPF, the changes in polymer yield were insignificant, and the intrinsic viscosities of the copolymers of St and VAc were not affected by DiPF. Thermal properties of the copolymers with St, VAc, and VC were examined by DSC and TGA. Introduction of the DiPF unit to poly-St and poly-VC showed no change in Tg when the content was less than 10mol%. Thermal decomposition temperatures of the copolymers with VAc and VC decreased with increasing content of the DiPF unit.View full abstractDownload PDF (1594K) -
Yoichiro MAKIMURA, Eri YOSHIDA, Toshio KITAO1997 Volume 54 Issue 2 Pages 79-86
Published: February 25, 1997
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSModification of polycarbonate (PC) with 2, 4-dihydroxybenzophenone (DHBP) was performed in the presence of FeCl3 as a catalyst in a twin screw extruder. The quantity of DHBP which had reacted with the end of PC in the reaction product was determined from the characteristic UV absorbance at 326nm which may be keto-enol tautomerization between the carbonyl and hydroxy group at 2 position of 2, 4-dihydroxyphenyl. The conversion of DHBP was almost linear with respect to both screw driving speed and reaction time. For example, the conversion increased monotonically with time and reached 100% after 23min, when PC involving 10-2eq. of DHBP and 5.0×10-4, eq. of FeCl3 to one carbonate bond was fed in the twin screw extruder and operated at 60 rpm of screw revolution rate at 255°C. The test piece prepared from the reaction product was subjected to an accelerated weathering test for evaluating the changes in its tensile and izod impact strengths, and compared with those of the test pieces made from raw PC and PC merely mixed with DHBP and FeCl3. After 144 h, no change was found in both strengths of the test piece prepared from reaction product, whereas significant decreases were recognized in tensile and izod strengths for the test pieces made from the latter two.View full abstractDownload PDF (1411K) -
Katsunori KOJIMA, Hajime NASU, Takeshi YAMAUCHI, Masato SHIMOMURA, Shi ...1997 Volume 54 Issue 2 Pages 87-93
Published: February 25, 1997
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSGlucose sensing with an electrode modified with poly (vinyl alcohol) (PVA) including glucose oxidase (GOD) and polypyrrole (PPy) was discussed. PPy/PVA/GOD composites were prepared on an electrode spincoated with PVA/GOD film by electropolymerization of pyrrole. Effects of the thickness of PVA/GOD film and the content of GOD in the film on growth of PPy was investigated by chronoamperometry and scanning electron micrography. It was found that the presence of GOD in the film led to acceleration of the polymerization of pyrrole and morphology of the PPy/PVA/GOD film. The activity of GOD was found to be independent of the film thickness. This result suggests that the enzyme reaction of GOD immobilized on the surface of the PPy/PVA/GOD film contributed to the current response to glucose. The current based on the reaction of GOD with glucose decreased rapidly with an increase of the film thickness on the electrode. It is considered that the electrons arising from the enzyme reaction were easily trapped in the PPy/PVA/GOD film due to an increase of the film thickness.View full abstractDownload PDF (3029K) -
Sadao HAYASHI, Seitaro ONOUE, Tsuyoshi HATAMACHI, Miho NAKAMURA, Jiro ...1997 Volume 54 Issue 2 Pages 94-101
Published: February 25, 1997
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe chromism of partially saponified poly (vinyl alcohol) (P-PVA) in organic solvents has been investigated. P-PVA was colored in organic solvents having a refractive index close to that of P-PVA. As the amount of residual vinyl acetate unit in P-PVA increased, the coloration of P-PVA became clear, and the maximum of the transmitted light shifted to the long wavelength side. The color of the transmitted light was complementary to that of the scattered light. This indicates that an intersecting point of the dispersion curve of P-PVA and that of organic solvent was in the visible region, and that the light at the intersecting point transmitted P-PVA and the other was reflected by P-PVA. As the refractive index of organic solvent decreased, the maximum of the light transmitted P-PVA shifted to the short wavelength side. When methanol having a low refractive index was added to an organic solvent having a high refractive index, the maximum of the light transmitted P-PVA was shifted from the short wavelength side to the long wavelength side with a small amount of methanol, and was conversely shifted from the long wavelength side to the short wavelength side with a large excess of methanol. These interesting phenomena were attributed to the competition between the decrease in the refractive index of P-PVA due to a selective adsorption of methanol from the mixed solvents and the decrease in the refractive index of the mixed solvents by the addition of methanol.View full abstractDownload PDF (1548K) -
Akihiro SUZUKI, Yoshinori SATO, Toshio KUNUGI1997 Volume 54 Issue 2 Pages 102-107
Published: February 25, 1997
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSTo produce the high modulus and high strength fiber, a continuous zone-drawing (CZD) /zone-annealing (CZA) method was applied to poly (ethylene terephthalate) fibers. By this method, we are able to draw and anneal fibers at a running speed of 500 mm/min. The running speed in the CZA gives a fifty-fold improvement as compared to a conventional zone-annealing. The CZD was carried out at a drawing temperature of 130°C under an applied tension of 12.3 MPa, and the CZA at 250°C under 146.9 MPa. The CZA fiber obtained has a birefringence of 0.256 and a crystallinity of 55%. The CZA fiber has a Young's modulus of 16 GPa and a storage modulus of 17 GPa at 20°C. The mechanical properties of the CZA fiber are approximately the same as that of the ZA fiber.View full abstractDownload PDF (3848K) -
Tadaoki OKUMOTO, Takao YAMADA, Shin TSUGE, Hajime OHTANI1997 Volume 54 Issue 2 Pages 108-114
Published: February 25, 1997
Released on J-STAGE: July 27, 2010
JOURNAL FREE ACCESSEthylene-propylene-diene (EPDM) rubber cured with sulfur and accelerators were characterized by high resolution pyrolysis-gas chromatography with both a flame ionization detector and a sulfur-selective flame photometric detector. For curing with sulfur and 2-mercaptobenzothiazole accelerator, two kinds of sulfur-containing products, such as C7H6S and benzothiazole, are typically observed in the pyrogram. The former is supposed to be formed from sulfur bridges to ethylidenenorbornene residue in the polymer chain through cyclization, while the latter is considered to be derived from the pendant accelerator residue. The vulcanization process for EPDM rubber is discussed on the basis of the relationships between the peak intensities of the characteristic products and cure time.View full abstractDownload PDF (1060K) -
Shuji SAKOHARA, Teruyuki KOSHI1997 Volume 54 Issue 2 Pages 115-118
Published: February 25, 1997
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSIn the previous paper [S. Sakohara et al., Kobunshi Ronbunshu, 52, 155 (1995)], it was reported that dimethylaminoethyl methacrylate (DMAEMA) gel formed in the pores of thin, porous ceramic membrane was useful for separation of benzene/cyclohexane mixtures. In order to clarify the effects of the tertiary amine groups in DMAEMA gel on the affinity and the selectivity for benzene, similar experiments were carried out by using ethyl methacrylate (EMA) gel whose chemical structure is basically similar to that of DMAEMA gel except for the tartiary amine group. Both gels swelled only slightly in cyclohexane, but swelled to similar large degrees in benzene. The fact suggests that the electrophilic actions of the carboxylic ester groups included in both gels contribute to the affinity for benzene. The excess amount of benzene taken into DMAEMA gel in benzene/cyclohexane mixtures, however, was larger than that taken into EMA gel. The results indicate that the tertiary amine groups in DMAEMA gel affect the selectivity for benzene. Furthermore, although the selectivity for benzene through DMAEMA gel membrane decreased with increasing the separation temperature as shown in a previous paper [S. Sakohara et al., Kobunshi Ronbunshu, 52, 155 (1995)], that through EMA gel membrane was not dependent on it at all. From these results it can be concluded that the tertiary amine groups in DMAEMA gel largely affect the selectivity for benzene.View full abstractDownload PDF (759K)
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