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Predecessor
Volume 36, Issue 9
Displaying 1-11 of 11 articles from this issue
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Osamu HAYASHI, Kazuya JINDA, Tooru TAKAHASHI, Haruo UENO1979 Volume 36 Issue 9 Pages 567-573
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSViscosity of carboxyl and hydroxyl terminated butadiene-acrylonitrile copolymers was determined by varying the combination of terminal functional groups, the degrees of functionality, and copolymer composition. Viscosity was measured using a cone-plate or couette type viscometer at 20-100°C. The polymers were Newtonian and their viscosity varied depending on the type of polymer terminal groups in the order of -COOH> (-COOH & -OH) > -OH. The Andrade equation was recognized in relation to temperature. Activation energies of the polymers were in the same order with the magnitude of the viscosity depending on the polymer terminal groups. Log viscosity of the copolymers was in proportion to the acrylonitrile content in the copolymer. 18C NMR signals of the copolymers show that acrylonitrile units are individually distributed in butadiene sequences. Viscosity increase by the special structure such as acrylonitrile block or continuous sequence was improbable. These results lead to the conclusion that the viscosity of the copolymerincreased by the association of the polar functional groups.View full abstractDownload PDF (1088K) -
Hiroshi SAKAMI, Toyohiko IZUSHI1979 Volume 36 Issue 9 Pages 575-580
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe high-melting-point crystal (HC) in high-molecular-weight polyethylene fibril (Mw=6×105-1×105) crystallized under stretching above the melting point were investigated by means of differential scanning calorimetry (DSC) and wide angle X-ray measurements. The HC appeared in these fibrils by stretching ratios of 8-15 at 138-150°C. For the sample stretched at stretching ratio of 15 at 150°C, the amount of the HC measured by DSC method was 10% of the fibril. Lattice constants of the HC measured with wide angle X-ray at 137°C or 140°C coinside with those of orthorhombic polyethylene crystal. This suggests an extended-chain crystal growth of the HC. Its melting point determined with DSC at the heating rate of 0.625°C/min was 150.5°C.View full abstractDownload PDF (872K) -
Akira YOSHINO, Jun NIKI, Joji YATSUNAMI, Seizo MIYATA, Kiichiro SAKAOK ...1979 Volume 36 Issue 9 Pages 581-587
Published: September 25, 1979
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSHighly oriented-extended-chain crystals of polyethylene (OE) were obtained by crystallization from the anisotropic melt under high pressure more than 3kbar. The anisotropic melt was thought to exist only for a short time when the drawn polyethylene was melted. The formation of OE depended strongly upon the melting time during which the transformation from anisotropic to isotropic melt took place.
Electron micrograph of the film (OE) showed a lamellar structure packed zigzag closely each other, whose average thickness was about 4, 000Å. The DSC thermogram gave a single endothermic peak at 143°C, and the degree of crystallinity was 92%. High tensile modulus and very high thermal stability were observed. Furthermore, the remarkable transparency like glass was appeared in this large OE.
From these facts, crystal orientation, voids, and flatness of surface are more important than the crystal size in the appearance of transparency.View full abstractDownload PDF (2205K) -
Hiroshi HATA, Yoshimasa HAMA, Koichi IBATA, Hitoshi KAWASAKI, Haruo NA ...1979 Volume 36 Issue 9 Pages 589-595
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSStress-strain relationships during the extension of unfilled and calcium carbonate-filled SBR were measured with a Tensilon Instrument at a fixed temperature. The results were analysed by the theories of rubber elasticity, Mooney-Rivlin and Furukawa, and the parameters involved in these theories were numerically examined. Although the tensile stress of the filled SBR at a fixed strain appeared to be slightly higher than that of the unfilled SBR, the number of the molecular chains per unit volume of the filled samples calculated according to the theory of rubber elasticity were less than those of the unfilled samples. Stress relaxation and dynamic modulus were also measured on these unfilled and filled samples. The relaxation spectra were calculated by employing several approximation methods. Stress-strain relationships during the extension were calculated according to the BKZ theory. The time dependent potential energy functions in the theory were replaced by the relaxation spectra. The computed stress-strain relationships were close to the observed ones. This method seemed to be applicable to predict the stress-strain behavior at different rate of extension.View full abstractDownload PDF (1160K) -
Takashi KAMON1979 Volume 36 Issue 9 Pages 597-601
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSRelation between the molecular structure and dynamic mechanical properties of epoxy resins cured with aliphatic polyamines has been studied.
On the epoxy resin-polyethylenepolyamine systems, when the number of active hydrogen atoms in the amine was increased from 4 to 6, e. g., ethylenediamine (EDA), diethylenetriamine (DETA), and triethylenetetramine (TETA), the crosslinking densityρ (E′) of cured resins increased, but front factor φ′ and glass-transition temperature Tg did not increase.
TETA, dipropylenetriamine (DPTA), and MeDPTA have nearly same molecular weight and 6, 5, and 4 active hydrogen atoms, respectively. For these amine-resin systems, ρ (E′), φ′, and Tg increased greatly with the increase of the number of active hydrogen atoms in amine.
ρ (E′), φ′, and Tg, of star type polyamine, e. g., trimethylaminohexane (TMAH) were slightly higher than those of linear type polyamine, e. g., TETA which had same active hydrogen atoms in TMAH.View full abstractDownload PDF (840K) -
Toyoji TSUCHIHARA, Seiichiro SAKIMOTO, Masaru KUBO1979 Volume 36 Issue 9 Pages 603-608
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSIn order to prepare aqueous ethylene-vinyl acetate emulsions for paints, the “semi-batch process at the elevated temperature” we developed was applied to the copolymerization in the presence of protective colloids. First, the relations of ethylene contents of copolymers and degrees of polymerization to paint properties (brushabilities) were studied, and it was found that the copolymers having ethylene contents of 8-12 wt% and degrees of polymerization not less than 800 had good paint properties. Secondly, the relations of polymerization conditions to paint properties were studied, and it was found that the amount of protective colloids preferably used was 0.5 wt% of the whole charge. The ethylene-vinyl acetate emulsions prepared thus under the optimum conditions were excellent vehicles for paints.View full abstractDownload PDF (1076K) -
Hiroshi NARUKAWA, Shuji KAWAI, Takio TASAKA, Haruo NAKAYASU1979 Volume 36 Issue 9 Pages 609-615
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSTemperature and sonic velocity were measured in the course of curing of unsaturated polyester resin and its compound. A device to compensate curing shrinkage of the sample was attached to the instrument for the sonic velocity measurement. In many cases, sonic velocity increases rapidly around the time when temperature of the sample becomes maximum and then increases gradually toward an equillibrium value. The sonic velocity at each stage of curing depended on the composition and temperature of the sample resin. The temperature of the sample varieddepending on the curing condition including the sample shape. In addition, dynamic viscoelasticity of a matured unsaturated polyester resin was measured by torsional braid analysis method. The mode of softening which was followed by successive hardening of the matured resin with temperature elevation was represented by the change in dynamic modulus and loss tangent.View full abstractDownload PDF (1227K) -
Toshihiro KASHIMA, Kuniomi ETOO1979 Volume 36 Issue 9 Pages 617-624
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe change in melting temperature (MT) for terephthalate copolyester (I) was studied by differential scanning calorimeter (DSC) and nuclear magnetic resonance (NMR) as a function of annealing time or temperature. The MT of I increased by annealing I both above and below the MT, and this was found to result from the conversion of random I to block by ester interchange. The activation energy for the increasing in MT depended on the range of annealing temperature and was larger below the melting temperature (Tm) 0 of untreated I than above. The influence of oxygen for the increasing in MT was discussed. The degree of increase in MT of I composed of 1, 4-buthanediol was more remarkable under vacuum than in air. These MT of I were recovered to (Tm) 0 by annealing at their polymerization temperature of 270°C.View full abstractDownload PDF (1226K) -
Tohei YAMAMOTO, Tadahiro YAMAMOTO, Jiro IZUKAWA, Masayoshi HIROTA1979 Volume 36 Issue 9 Pages 625-628
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe radical polymerization of vinyl acetate in various concentration of benzene solutions was carried out at 30°C under light irradiation of 366 nm wavelength and by using 1, 1′-azobiscyclohexanecarbonitrile (ACN) as a photosensitizer. The rate of polymerization (Rp) changed markedly with the change of the solution concentration, while the rate of initiation (Rl) scarcely changed. The values of kp and 2kt were derived by means of rotating sector method. The value of kp changed markedly with the change in the solution concentration, Rp/ [M] being proportional to kp. The value of 2kt scarcely changed with the concentration. The effect of the concentration on the stereoregularity of PVAC was found scarce.View full abstractDownload PDF (651K) -
Bun-ichiro NAKAJIMA, Norio NISHI, Junzo NOGUCHI1979 Volume 36 Issue 9 Pages 629-634
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPoly (L-methionine) was converted by reduction with sodium in liquid ammonia under various conditions into seven kinds of poly (L-methionine-co-L-homocysteine) s having the homocysteine contents of 11, 19, 26, 44, 72, 81, and 88% (mol%). The conversion into L-homocysteine units of up to 80% can be reproduced under relatively mild conditions. Although the solubilities of the copolymers in organic solvents decrease with an increase of homocysteine content, all the copolymers prepared are soluble in methanesulfonic acid and trifluoromethanesulfonic acid. The copolymers were found to have a random coil conformation in methanesulfonic acid and a random coil structure containing some ahelical conformation in dichloroacetic acid, by viscometric measurement and optical rotatory dispersion. On the other hand, their conformations in a solid state were determined to be a mixture of α-helix and β-form from the infrared absorption spectra.View full abstractDownload PDF (1002K) -
Tatsuro OUCHI, Masayoshi OIWA, Minoru IMOTO1979 Volume 36 Issue 9 Pages 635-637
Published: September 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSIn 1944, Imoto has proposed the mass distribution function mA for phenol-novolak resin:
mA=AcQa
QA=α1α2αA-1, αA=h-gA
where A is tne degree of addition-condensation (for example, A of C6H4 (OH) -CH2-C6H4 (OH) is 2); αA-1 is a propagation probability of the reaction (A-1→A); c is an average termination probability; h and g are the constants. The equation (αA=h-gA) can be replaced by (αA=he-o (A-1) ). When the reaction time of novolak formation was long, the resin was reformed and the mA became to obey Poisson distribution function. From these mA, the ratios of Mw/Mn were calculated theoretically, and they were found to agree with the Mw/Mn ratios which were obtained experimentally from GPC measurements.View full abstractDownload PDF (296K)
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