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Volume 43, Issue 7
Displaying 1-11 of 11 articles from this issue
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Ryoichi MURAKAMI1986 Volume 43 Issue 7 Pages 389-393
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe thixotropy of a concentrated colloidal solution of starch-boron complex compounds was investigated by measuring its viscosity using a rotation viscosimeter. The values of the viscosity of the colloidal solution decreased due to agitation, but increased to the initial values after about an hour. The time dependence of the values of the viscosity was measured and the results were analyzed by rate theory. The pocess of the formation of associated structure could be expressed by a first-order equation; the activation energy for the formation of associated structure was approximately 16 kcal/mol. By adding sodium chloride, the degree of the thixotropy of the colloidal solution decreased remarkably. This suggests that the thixotropy is mainly caused by some interaction, such as electrostatic repulsive force.View full abstractDownload PDF (686K) -
Shogo KOBAYASHI, Hiroshi SATO1986 Volume 43 Issue 7 Pages 395-398
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSIn order to investigate the long-term stability of polyester resin concrete under water, the resin concrete was immersed in Kusatsu hot spring (43°C, pH 1.8-2.3) and Yuze hot spring (66°C, pH 9.3-9.5) for 15 years, and the flexural and compressive strength were measured as a function of immersion time. It was shown that after an induction period an approximately linear relationship exists between the flexural or compressive strength and the logarithm of the time. The retention in mechanical strength of the resin concrete immersed in Kusatsu hot spring for 15 years was about 78%, and that in Yuze was about 64%. Using these results and the results which had been obtained from accelerated experiments in water, an experimental equation for durability of polyester resin concrete in water was derived.View full abstractDownload PDF (645K) -
Tadaya KATO, Hideaki ASAMI, Akira TAKAHASHI1986 Volume 43 Issue 7 Pages 399-404
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSTwo series of hydroxypropyl methylcellulose (HPMC) samples with different degrees of substitution were adsorbed from aqueous solutions onto two kinds of alumina surfaces differing in particle diameter. Each series consisted of four carefully fractionated samples having different molecular weights. Adsorbance was estimated from the decrease in peak area of chromatograms measured by an aqueous GPC. The adsorption isotherms were not high-affinity types. Isotherms were gradually increasing over low polymer concentration region and plateau values were reached at high concentration. The equilibrium adsorbances A (g/cm2) estimated by the limiting plateau values appeared to be much higher than those in the ordinary cases of polymer adsorption. The A values were also greatly dependent on molecular weight. The average segment concentration in adsorbed layer could be estimated by the surface area of alumina and the adsorbance A, assuming that the thickness of the adsorbed layer contributed twice as much as the radius of gyration. The abnormally high segment concentration thus estimated suggests that the characteristic behavior of HPMC adsorption onto alumina surfaces will be as follows: that the adsorbed polymer layer displays a semidilute-gel transformation on surfaces and that both A and the thickness of adsorbed layer thus increase very much.View full abstractDownload PDF (1464K) -
Eiji IKADA, Masafumi KIMURA, Michio ASHIDA1986 Volume 43 Issue 7 Pages 405-412
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPolystyrene is irradiated in benzene, chloroform or carbon terachloride by UV light, and the number of main-chain scission is determined by viscosity measurement and GPC analysis. The main-chain scission is much faster in chloroform and carbon tetrachloride than in benzene. Addition of chloranil as a photosensitizer significantly accelerated the scission in benzene. The products are composed of degradated polystyrenes and some low molecular weight fraction (ca. 120) which possesses phenyl, methyl, and methylene groups. On the irradiation in chloroform, one chlorine atom per four monomeric units of polystyrene is introduced to the degradation products. Here, radical species formed by the photochemical cleavage of chloroform play an important role in the main-chain scission of polystyrene.View full abstractDownload PDF (1231K) -
Norio TSUBOKAWA, Hiroki MINOWA, Yasuo SONE1986 Volume 43 Issue 7 Pages 413-417
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPolyamideimide (PAI) samples were prepared from 4, 4′-diphenylmethane diisocyanate (MDI) and trimellitic anhydride (TMAH) containing 8.0 mol% of trimellitic acid (TMA), and their viscosity behavior was investigated. The reduced viscosity vs. concentration curves for PAI in N-methyl-2-pyrrolidone (NMP) were markedly concave upward at low concentration, exhibiting polyelectrolyte behavior. Similar behavior was observed in N, N-dimethylformamide, but not in m-cresol. The polyelectrolyte behavior disappeared when PAI was treated with phenyl isocyanate at 110°C for 12 h or when NaSCN was added to NMP solutions of PAI. But PAI prepared from MDI and purified TMAH, which contained 0.13 mol% of TMA, showed ordinary viscosity behavior in NMP. From these findings, it was concluded that PAI prepared from unpurified TMAH has an amic-acid structure and that the polyelectrolyte behavior is due to the carboxyl group in this structure.View full abstractDownload PDF (770K) -
Katsutoshi TANAKA, Kimihiro ADACHI, Yuko TANAKA, Hiromasa OGAWA1986 Volume 43 Issue 7 Pages 419-427
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPoly (vinyl chloride) samples filled with glass beads (GB) and treated with titanate coupling agents (TCA) in the range of 0-70 vol% have voids around the glass particles. The volume fraction of voids increases abruptly at about 0.5 of the volume fraction of GB (φf), after which φf reaches constant values. The maximum packing values (φfm) are 0.59-0.63 for the untreated systems and those treated with TCA, and 0.58-0.62 for the system treated with silane coupling agent. Dynamic mechanical properties of the composite materials were measured over the temperature range from room temperature to about 130°C. The enhancement of the glass-transition temprature (Tg) is small below 0.4 of φf, while it becomes higher near φfm. The relative modulus (Er′) for the composite materials of small GB is larger than those of medium and large GB over all the φf range. In the glassy region, Er′ is less than 1.6 for the untreated systems and 2.0 for the treated systems, these values are lower than the value estimated from the modified Halpin-Tsai's equation, using a modified Einstein coefficient of 2.5. In the rubbery region, Er′ values are lower than that estimated from Mooney's equation.View full abstractDownload PDF (2047K) -
Masayoshi OKUBO, Seitaro YAMAGUCHI, Tsunetaka MATSUMOTO1986 Volume 43 Issue 7 Pages 429-434
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSA composite polymer emulsion was prepared by the seeded emulsion copolymerization of styrene and sodium p-styrene sulfonate by using butyl acrylate-methacryloyloxyethyltrimethylammonium chloride copolymer particles as the seed. It was observed that films of the composite emulsion changed from the untacky to tacky on heat treatment. Effects arising from factors such as heat treatment condition and polymer composition were investigated.View full abstractDownload PDF (1033K) -
Zun-Kui CAO, Koichi UTE, Tatsuki KITAYAMA, Yoshio OKAMOTO, Koichi HATA ...1986 Volume 43 Issue 7 Pages 435-441
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPolymerizations of MMA were carried out in polar solvents at low temperatures with the use of Grignard reagents RMgBr (R=CH3, C2H5, n-C4H9, iso-C4H9, s-C4H9, t-C4H9, C6H5, C6H11) and the effects of solvent, additive, and temperature on the polymerizations were studied. With an increase in the bulkiness of alkyl groups of the Grignard reagents, the initiator efficiency and polymer yield increased and the molecular weight distribution of the polymer became narrower. This was ascribed to prevention of the side reactions of the Grignard reagents by bulky alkyl groups. The methanol-insoluble PMMA prepared in a mixture of tetrahydrofuran-dimethoxyethane (8/2 vol/vol) at -110°C had Mw/Mn, of 1.39 and syndiotactic triads of 94.9% This method is useful for the preparation of highly syndiotactic PMMA with narrow molecular weight distribution.View full abstractDownload PDF (1102K) -
Norio TSUBOKAWA, Miki SAKAGUCHI, Isamu YAMAMOTO, Yasuo SONE1986 Volume 43 Issue 7 Pages 443-447
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPolyamideimide (PAI) prepared from trimellitic anhydride (TMAH) and 4, 4′-diphenylmethane diisocyanate (MDI) was fractionated by fractional precipitation. The effects of molecular weight on the structure and thermal stability of PAI were investigated. (1) The low molecular weight fraction, whose intrinsic viscosity ([η]) in N-methyl-2-pyrrolidone at 30°C was 0.13dlg-1 contains fewer imide bonds than high molecular weight fractions with [η] of 0.29 dlg-1 or higher. But the former contains many more amide bonds than the latter. This suggests that amic acid bonds are preferentially formed in the initial stage of the polycondensation by the reaction of MDI with trimellitic acid (TMA) which may be contained in TMAH. (2) The weight loss of PAI fraction with [η] of 0.13dlg-1 on heating was more than that of PAI fractions with [η] of 0.29 dlg-1 or higher in the range of temperature from about 300°C to 530°C. Except for the above temperature ranges, no differences in thermogravimetric curves of these fractions were observed. (3) The thermogravimetric curve of PAI with [η] of 0.11dlg-1 prepared from sublimed TMAH was almost equal to that of PAI fractions with [η] of 0.29dlg-1 or higher.View full abstractDownload PDF (838K) -
Hiroyasu ISHIDA, Masako WATANABE, Sabura KAMAGAMI1986 Volume 43 Issue 7 Pages 449-452
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSSeparation of ethanol-water mixture was carried out by the pervaporation technique through chitosan membranes treated in various ways. The permeation rate Q increased in the following order: the membrane dried on a filter paper (DFM) < the membrane dried on a glass plate (DGM) <the membrane immersed in water (WM). The separation factor a was in the order that DFM > DGM > WM. In the pervaporation through DFM of 10 μm thickness at 70°C, the products of α and Q at 80% and 92% of the ethanol contents in feed were 100 and 51 kg/cm2h, respectively.View full abstractDownload PDF (595K) -
Shinichi SUTO, Satoru KIMURA, Mikio KARASAWA1986 Volume 43 Issue 7 Pages 453-457
Published: July 25, 1986
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe order parameter S of a cholesteric liquid crystal of the hydroxypropyl cellulose/dimethylacetamide system was calculated using refractive index data. Two approaches were used: method 1 used solid-state data, and method 2 was Haller's extrapolation approach. The S values obtained using method 1 lay in the range of 0-0.9 and the S values calculated using method 2 were in the range of 0.4-0.5, within our experimental range. The S values depended on temperature and concentrtion, and could be generalized by a master curve. Although both approaches involved implict problems, method 2 is preferable for estimating S values of lyotropic liquid crystals.View full abstractDownload PDF (837K)
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