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Volume 36, Issue 3
Displaying 1-10 of 10 articles from this issue
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Kazuo OKAHASHI, Michio FUTAKUCHI, Kyoichi SHIBAYAMA1979 Volume 36 Issue 3 Pages 135-139
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSIn order to elucidate the curing reaction of epoxy resin with zinc diethyldithiocarbamate (I), the bulk and solution (in methanol or toluene) polymerization of phenyl glycidyl ether (II), a model compound of epoxy resin, by I was investigated kinetically. The rate of bulk polymerization is expressed by the following equation:
-d [PGE] /dt=k3 [II] [I] 2
The activation energy and the activation entropy are 13.4 kcal/mol and -25 cal·mol-1·deg-1, respectively. The rate constant for the polymerization in methanol is larger and that in toluene is smaller than the value for the bulk polymerization. In the polymerization of II by various zinc dithiocarbamate, the rate increases with decreasing the size of group attached on the amino group. It is suggested that the ring-opening reaction of the epoxide proceeds through an SN2 mechanism in which N atom and Zn atom in I interact with the epoxy ring simultaneously to form a cyclic complex.View full abstractDownload PDF (802K) -
Kazuo INOUE, Sadao HOSHINO1979 Volume 36 Issue 3 Pages 141-146
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSWater sorption behavior of a quenched amorphous sample of an aromatic polyamide, poly (m-xylylene adipamide), was studied. Under low humidities at 50°C the sorption showed no abnormal behavior, while under humidities higher than ca. 60% the absorption markedly decreased after it had reached a maximum. By the changes of X-ray diffraction and thermal properties of the sample by the absorption, the above result was attributed to the crystallization of the sample which was induced by the lowerings of glass transition and crystallization temperatures due to water absorption, The reduction of moisture regain by the crystallization was nearly equal to the reduction of amorphous content. This means that water is excluded from the polymer phase as it crystallizes and this excluded water does not remain between the crystalline phases but leaves the polymer.View full abstractDownload PDF (1394K) -
Kazuo INOUE, Sadao HOSHINO1979 Volume 36 Issue 3 Pages 147-153
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSProcess of water-induced crystallization of poly (m-xylylene adipamide) was analysed with the aid of observed data on moisture regain change by the crystallization. The relation between the reduction in moisture regain and that in amorphous content by the crystallization manifests that water is completely excluded from crystal by the crystallization. So, the moisture regain change in the water induced crystallization is attributed to the three processes, (1) absorption, (2) exclusion of water from crystal by the crystallization, (3) diffusion of the excluded water. These processes were analysed by the numerical calculation of diffusion equation combined with crystallization equation. The result was in good agreement with the observed data. By the analysis of the calculated result, the process of the crystallization and the behavior of water in the crystallization were examined.View full abstractDownload PDF (1229K) -
Toshikazu FUJIMURA, Hiroshi SUZUKI1979 Volume 36 Issue 3 Pages 155-161
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSTo produce continuously the molecular composites containing extended-chain crystal (ECC) of high-density polyethylene, polymer melts were extruded through a coverging slit die. Effects of elongational flow and of blending on the tensile modulus and on the crystallinity, and the possibility of the processing of molecular composites containing ECC were discussed. (1) The tensile modulus increased with the increases in the elongational ratio and in the elongational rate, but only a little increase in the crystallinity was observed. This might be caused by the restriction of the elongational rate due to the instability of flow or by the insufficient Deborah number. (2) At a lower extrusion temperature, the extrudate solidified in the die, but its tensile modulus and its crystallinity increased. (3) Blending of the samples having largely different viscosities improved the tensile modulus, the crystallinity and the stability of flow. (4) The molecular composite could be produced continuously by means of drawing immediately after extrusion or by increasing the extrusion pressure.View full abstractDownload PDF (1129K) -
Yukihiko SATO1979 Volume 36 Issue 3 Pages 163-168
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe dielectric losses (tan δ) at 500 MHz in high-, medium- and low-pressure polyethylenes have been measured at 23°C. The crystallinities (χw) were controlled by heat treatments. The tan δ decreased linearly with the increase in the crystallinity and was almost zero at χw=100%. The change in tan δ was reversible on repeated heat treatments. χw was calculated from the values of the crystalline density, ρc=1.014 g/cm3, and the amorphous density, ρa=0.850 g/cm3. The former was estimated from the crystal lattice constant of non-branching polyethylene and the latter from the thermal change in the specific volume of n-paraffin.View full abstractDownload PDF (1075K) -
Yoichi SHIMOKAWA, Hajime MIYAMA1979 Volume 36 Issue 3 Pages 169-174
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSN-Allyloxymethyl-poly (ε-caproamide), prepared by the reaction of formaldehyde and allyl alcohol with poly (ε-caproamide) in the presence of formic acid, has been found to be a highly-sensitive electron-crosslinkable polymer. Polyamides of N-allyloxymethylation degrees over 25 to 30% are soluble in alcoholic solvents, such as methanol and ethanol-water mixture, and are conveniently usable for electron beam lithography. Polymer with 35 to 40% N-allyloxymethylation degree exhibits the best lithographic qualities, the minimum exposure for insolubilization being 5×10-8 coulomb/cm2. This high sensitivity, together with an excellent resolution, makes it one of the most promising materials for electron beam lithography. By addition of photosensitizers, such as aromatic ketones, it can be utilized as a photocrosslinkable material.View full abstractDownload PDF (952K) -
Seiichi KATAOKA, Tadanao ANDO1979 Volume 36 Issue 3 Pages 175-181
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSRegenerated chitin films were made by casting chitin solutions in mixtures of trichloroacetic acid (TCA) and halogenohydrocarbons such as dichloromethane, chloroform, and 1, 2-dichloroethane (DCE). The acidic binary solvents of DCE and TCA (25-67 wt%) dissolve chitin. The best amount of TCA was 35-40 wt%. The chitin solution was stored for three days below 5°C or for six hours at 15°C without significant decomposition. Rapid decomposition of the chitin in the solution at room temperature (27-32°C) was suggested from the decrease of the tensile strength of the films prepared from this solutions. The casting films in optimum conditions had tensile strength of 9.4 to 9.5 kg/mm2, and were quite tough, hygroscopic and cellophane-like. Elemental analyses of the films indicated the same composition as the purified native chitin, which was supported by infrared spectrum.View full abstractDownload PDF (1290K) -
Tetsuo MORI, Tetsuro YAMADA, Ryuichi TANAKA, Takehide TANAKA1979 Volume 36 Issue 3 Pages 183-187
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSConcentrated solutions of poly (L-glutamic acid) (PGA) and poly (oxyethylene glycol) (PEG, Mn=300), and the solid films prepared by casting them were investigated by means of small-angle light scattering and polarizing microscopy. N, N-dimethylformamide (DMF) and dioxane-water mixtures (D-W, 3: 1 v/v) were used as solvents. In all the concentrated solutions, irrespective of the relative content of PGA and PEG, the cholesteric liquid crystal structure was observed both in DMF and in D-W. Concerning the solid films prepared by evaporating DMF, two different states of aggregation were recognized depending on the PGA content. The films with a PGA content of 100 or 90 wt% gave rise to the HV pattern typified by the 0-90° cross (+ type); their polarizing micrographs showed aggregates of rodlike texture. The HV patterns changed to the ±45° cross (×-type) with the films containing 80-40 wt% of PGA and the micrographs typical of cholesteric liquid crystal structure were obtained. All the films cast from D-W, on the other hand, showed ×-type HV patterns. Spherulitic cholesteric structure and/or the retardation lines were observed.View full abstractDownload PDF (1683K) -
Tetsuo MORI, Tetsuro YAMADA, Ryuichi TANAKA, Takehide TANAKA1979 Volume 36 Issue 3 Pages 189-192
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSHeterogeneous network polymers were prepared from poly (L-glutamic acid) (PGA) and poly- (oxyethylene glycol) (PEG, Mn=300) using dioxane-water mixture (D-W, 3: 1 v/v) as a solvent. The PGA content was varied from 100 to 40 wt%. As the PGA content increases, (1) the inter-helical distance widens in accordance with the Robinson's equation; (2) the cholesteric pitch increases and the angle of twist per layer in the cholesteric structure decreases; and (3) the peak temperature of tan δ shifts to a lower side. These results are consistent with the supposition that the hexagonally packed α-helices of PGA constitute the cholesteric liquid crystal structure and that the PEG chains are accommodated within the interstices of α-helices.View full abstractDownload PDF (1115K) -
Masato KODAKA1979 Volume 36 Issue 3 Pages 193-195
Published: March 25, 1979
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe multiple membrane composed of a hexokinase-immobilized gelatin membrane, an alkaline phosphatase solution layer and cellulose membrane was prepared, and the permeabilities of D-glucose and D-xylose through this multiple membrane were investigated. The kinetic constants of free hexokinase, immobilized hexokinase and free alkaline phosphatase were determined. The activity of the immobilized hexokinase was ca. 30% of the free enzyme activity, and the apparent Michaelis constant was ca. 54 times as large as that of the free enzyme. As was expected, the permeation rate of xylose through the multiple membrane was greater than that of glucose. The perm-selectivity decreased with time, and it was a little higher when the initial concentration of sugar was low. In the absence of ATP, little selectivity could be seen.View full abstractDownload PDF (495K)
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