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Volume 38, Issue 3
Displaying 1-9 of 9 articles from this issue
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Shigehiro NAGURA, Shinichiro NAKAMURA, Yoshiro ONDA1981 Volume 38 Issue 3 Pages 133-137
Published: March 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe mechanisms of the thermally-reversible gelation of cellulose ethers (methylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose) were studied. The temperature-viscosity relationships were measured for aqueous solutions of the cellulose ethers by the method of oscillation viscometry. The gelation temperature of the methylcellulose-water system depends on the heating rate, and the feature of the thermal-histeresis curve shows that the onset of gelation depends on the thermodynamic conditions consistent with a crystal-liquid transition. In the case of the hydroxypropylmethylcellulosewater system, on raising the temperature, the viscosity decreases sharply at a temperature T1 because of a sort of liquid-liquid phase separation of -OC3H6OH groups, and then the viscosity rises at a temperature T2 because of the formation of cross-linking. T1 is independent of heating rate, polymer concentration, and degree of polymerization. T1-point is determined by the values of degree of substitution (-OCR3 groups) and also molar substitution (-OC3H6OH groups). As heating rate decreases, T2 approaches T1. As the value of molar substitution increases, (T2-T1) increases.View full abstractDownload PDF (734K) -
Kenji SUMIYA, Toshiaki TAII, Katsuhiko NAKAMAE, Tsunetaka MATSUMOTO1981 Volume 38 Issue 3 Pages 139-144
Published: March 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe packing density and orientation of particles in magnetic coatings whose binders are polyester (PES) and partially-sulfonic polyester (PES-S) are investigated. The following results were obtained. (1) The dispersion, the packing density, and the orientation of particles in PES-S paints and coatings were significantly better than those of PES paints and coatings. Furthermore, the packing density of particles in PES-S coatings was affected by the solvent powers. (2) The adsorption of PES-S on γ-Fe2O3 and the lowering ability of interfacial tension of PES-S at the water/oil interface were larger than those of PES. From the comparisons of adsorption on γ-Fe2O3 and the surface pressure (π) -area (A) curves of monolayer for PES-S, it was confirmed that PES-S molecule adsorbed on γ-Fe2O3 in the form of train-loop (large loop) type, where the sulfonic groups acted as the anchor segments.View full abstractDownload PDF (977K) -
Masaki SHIMBO, Mitsukazu OCHI, Nobuki MATSUURA1981 Volume 38 Issue 3 Pages 145-151
Published: March 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe shrinkage and internal stress of bisphenol-type epoxide resins cured with aliphatic α, ω-dicarboxylic acids, HOOC- (CH2) p-COOH (p=2, 4, 7, and 8) have been investigated by measuring the changes of densities and internal stresses in the curing and the cooling processes.
The internal stress was caused by the shrinkage occured in the cooling process from the glasstransition temperature to room temperature. The shrinkage and internal stress increased with increasing concentration of network chains, with an elevation of glass-transition temperature in the cured systems, and with decreasing methylene chain length of the curing agents.
From the above observations, it was suggested that the reductions in concentration of network chains and in glass-transition temperature were neccesssary to reduce the shrinkage and internal stress caused by curing.View full abstractDownload PDF (1107K) -
Yukio UEMURA, Masajiro KOBAYASHI, Sadao YAMASHIRO1981 Volume 38 Issue 3 Pages 153-159
Published: March 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe influence of V-notch shape of test specimen on Charpy impact value has been experimentally studied for two kinds of engineering plastics, i. e., poly (oxymethylene) (POM) and polyamide (PA). The experiments were carried out for seven steps of notch root radius over a range of 0-2.0mm and ten steps of notch depth over a range of 0.1-5.0mm. The Charpy impact values were affected seriously by the notch shape, ranging from 2.4 to 82kgfcm/cm2 for POM and from 1.7 to 74kgfcm/cm2 for PA. The values increased with increasing notch root radius and with decreasing notch depth. A strong correlation between the Charpy impact values and the modes of fractured surfaces of broken specimens was found for POM and PA, as the same was found for poly (vinyl chloride), poly (methyl methacrylate) and polypropylene previously.View full abstractDownload PDF (5387K) -
Kazuo OKAHASHI, Osamu HAYASHI1981 Volume 38 Issue 3 Pages 161-167
Published: March 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe bulk and solution (in methanol) polymerization of phenyl glycidyl ether (I), a model compound of epoxy resin, by metal (Pb, Zn, Fe) caprylate (II) is investigated in order to shed light on the mechanism of the curing reaction of epoxy resin with II. The polymerization follows a second-order rate law with respect to I and II. Activation entropy in the ring-opening reaction of the epoxide, is largely negative and that for the solution polymerization is smaller than that for the bulk polymerization. Infrared spectra of I/II system clearly show the appearance of the ester linkage at 1, 730-1, 735 cm-1 and, at the same time, the disappearance of carbonyl group of II at 1, 510-1, 550cm-1. The ringopening reaction of the epoxide in the solution polymerization is suggested to proceed through an SN2 mechanism involving the formation of a cyclic complex composed of the metal ion, the hydroxyl group of methanol and the epoxy ring.View full abstractDownload PDF (963K) -
Hiroshi SAKAMI1981 Volume 38 Issue 3 Pages 169-174
Published: March 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe fine structure of simultaneously biaxially-stretched poly (ethylene terephthalate) (PET) films treated in the ethylamine aqueous solution (EAS) has been investigated by means of scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and wide- and small-angle X-ray (WAX and SAX) scattering measurements. The decomposition by use of a 60% EAS at 30°C for 1-8h, separates the films into skin and core phase. At the surface of the 2×2 stretched film under treatment by EAS at 30°C, many fibrils were observed as formed at the bottom of the cracks. DSC and WAX measurements of the 5×5 stretched film showed that the crystallinity of the skin phase was increased more than that of the core phase by EAS treatment. With an increase of the biaxially-stretching ratio of the film, the crystalline and amorphous polymer chains parallel to the film plane increased and also the amount of the skin phase increased. SAX measurements showed that the crystal size became smaller, from 80 to 40A, with the increase of the stretching ratio. From these facts, it is suggested that the chain orientation, which is parallel to the film plane near the surfaces, is increasingly randomized with the distance from the surfaces.View full abstractDownload PDF (2528K) -
Yoshiaki HIRABAYASHI, Hirokazu TAI, Shigeki TAKAYAMA, Yasuji OHTSUKA1981 Volume 38 Issue 3 Pages 175-181
Published: March 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSMembranes were prepared by casting the following graft copolymer latexes in air of 65% relative humidity at 20°C: (A) mixtures of acrylonitrile (AN), 2-hydroxyethyl methacrylate (HEMA), and one of the additives (ethylene glycol, glycerin, dimethyl phthalate, dibutyl phthalate, triacetin, dibutyl phosphite, and dimethylformamide) was added in aqueous poly (vinyl alcohol) solution and graft copolymerized using ceric ammonium nitrate (Ce4+ salt); (B) mixtures of AN, methyl acrylate (MA), and urea were added in aqueous poly (vinyl alcohol) solution and graft copolymerized in the same manner as the case (A). The membranes obtained by (A) had good water permeability retaining good mechanical properties in wet state, both of which were realized by choosing the appropriate composition of the additive to the monomers, for example, 20% ethylene glycol, 40% triacetin, and 30% dimethylformamide (by weight based on monomers). The improvement of water permeability was principally due to the vacant regions between the particles caused by the extraction of the additive with water at 80°C, as observed by field-emission scanning electron microscope. Water and solute permeabilities of the membranes obtained by (B) increased, and the mechanical properties in wet state decreased with the amount of urea added. Addition of 7 wt% urea based on monomers brought about good solute and water permeabilities with accompanying slight decrease in the mechanical properties in wet state.View full abstractDownload PDF (5466K) -
Tetsuya SHIOTA, Tokan KANAYAMA, Koichiro HAYASHI1981 Volume 38 Issue 3 Pages 183-185
Published: March 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSUltraviolet (UV) -induced polymerization of organic compounds having no polymerizable double bond was carried out in the gaseous phase. The aromatic compounds having hydrogen or halogen atom in the substituent groups, such as toluene, N-methylaniline, acetophenone, and benzyl chloride, could be polymerized by UV irradiation in the gaseous phase, probably, due to the formation of stable radical. However buthylamine, N, N-dimethylformamide, acetone, benzene, pyridine, and chlorbenzene could not be polymerized.View full abstractDownload PDF (466K) -
Yoichi KUROKAWA, Hideki NAKANO1981 Volume 38 Issue 3 Pages 187-188
Published: March 25, 1981
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSMembrane potential and desalination property were measured for the cellulose acetate membrane impregnated with hydrous manganese dioxide. By the impregnation, desalination did not increase but ion selectivity changed. The cellulose membrane devoid of manganese dioxide showed cationic selectivity in aqueous sulphate solution. The composite membrane showed cationic selectivity in aqueous calcium solution.View full abstractDownload PDF (313K)
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