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Volume 74, Issue 9
Displaying 1-8 of 8 articles from this issue
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Takashi YAMAMOTO2001 Volume 74 Issue 9 Pages 430-436
Published: September 20, 2001
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSDownload PDF (999K) -
Takenori DEGUCHI, Daisuke MIYAZAKI, Kenichi MASUHARA, Mitsunobu IWASAK ...2001 Volume 74 Issue 9 Pages 437-443
Published: September 20, 2001
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSZn-Ni-TiO2 composite films were successfully formed on steel plates by electroplating from a ZnSO4 NiSO4 mixed bath containing TiO2 particles. The uptake of TiO2 particles into the film (W) was found to increase with the addition of NH4NO3. Also, the value of W increased monotonically with increasing concentration of TiO2 in the bath (X, 0≤X≤200g L-1). The photocatalytic activity for the oxidation of CH3CHO reached a maximum at X=150gl-1 Electron probe microanalysis pointed out an intimate correlation between the photocatalytic activity and the depth distribution of the TiO2 particles. X-ray diffraction measurements indicated that the Zn-Ni metal phase in an optimum composition has γ phase with an excellent corrosion resistance.View full abstractDownload PDF (1135K) -
Kunio ESUMI, Kentaro SAKAGAMI, Kanjiro TORIGOE2001 Volume 74 Issue 9 Pages 444-449
Published: September 20, 2001
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSThe adsorption kinetics of poly (acrylic acid) (PAA) and sodium dodecyl sulfate (SDS) on alumina particles at pH 5.2 was investigated by measuring the amount of PAA and SDS adsorbed and the dispersion stability of suspensions with time. The adsorption of single systems of PAA and SDS showed a similar behavior that the adsorption increases rapidly and then saturates. In the simultaneous adsorption of PAA and SDS at two initial concentrations of SDS which correspond to the formation of a monolayer and a bilayer of SDS, respectively, the adsorption of PAA increased markedly at an early stage, decreased, and then became constant, while the adsorption of SDS exhibited a similar behavior to that of SDS alone. In addition, the dispersion stability of alumina suspensions with time was also affected by adsorption of PAA/SDS. The mechanism of adsorption kinetics of PAA and SDS on alumina particles was discussed.View full abstractDownload PDF (940K) -
Minoru TSUBOTA, Katsura NAGANUMA, Yukito WATANABE, Norihiro BABA2001 Volume 74 Issue 9 Pages 450-455
Published: September 20, 2001
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSIn this paper, we investigated the effective surface modification of Ag powders to improve the physical properties of the electric conductive paints. By adsorption of benzoic acid on Ag surface, we prepared modified Ag powders having various surface coverage ratio (SCR), and made the conductive paints by dispersing these powders in acrylic resin solution. Electric conductivity and the dynamic modulus in the rubbery region of the paint films had maxima at about SCR=50%. These results support our modification design, that is, the unmodified surface of Ag plays the role to connect the powders, and the modified surface acts to improve the interaction betwen the binder and the powders.View full abstractDownload PDF (806K) -
Shin-ichi TAKEDA, Isao TARI2001 Volume 74 Issue 9 Pages 456-459
Published: September 20, 2001
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSIn recent years, several developments have been made in ultrasonic attenuation spectroscopy for the monitoring of particle size distributions of highly concentrated slurries. This paper presents experimental proof that ultrasonic attenuation spectroscopy is capable of characterizing breaking-up and dispersed or flocculated paricle size in highly concentrated pigment slurries. Well-characterized TiO2 was used for testing the technique. The instrument for the measurement of ultrasonic attenuation spectra covers a wide frequency range from 3 to 100 MHz and converts them into particle size distributions. It is shown that the particle size distribution obtained before ultrasonication indicates the presence of aggregated particles, but after ultrasonication the aggregated particles are broken into smaller particles of which size nearly corresponds to the primary size. Change in particle size distribution during stabilization process can also be monitored. Hence we confirmed that this technique can detect the change in particle size distribution during breaking-up and stabilization processes without dilution.View full abstractDownload PDF (609K) -
Rie TOMITA, Satoshi URANO, Shigemi KOHIKI2001 Volume 74 Issue 9 Pages 460-465
Published: September 20, 2001
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSSilicic ester, an oligomer of tetraalkoxysilane is an additive of coatings for giving hydrophilicity to the coated film surfaces. However, its mechanism of hydrophilization is not yet clear. Because silicic ester can be persumed to be hydrolyzed after migrating to the film surface based on its hydrophobic nature, if the silicic ester content on the surface and the hydrolysis ratio can be determined separetely, they will provide usefull information for an elucidation of the mechanism. We found out that only alkoxy group of silicic ester in coated films was specifically decomposed on irradiation of non-monochromatized Mg Kα X-rays. The individual determining methods of the silicic ester content and the hydrolysis ratio of the surface using this phenomenon were developed. These methods were applied to the acryl-urethane coating which containing a silicic ester. It was found that the hydrolysis of silicic ester on the film surface was proceeding gradually after curing. A good correlation was obtained between silicic ester content and water contact angle on the surface of the film. In addition, the silicic ester content and the hydrolysis ratio of the surface indicated a good correlation to the water contact angle. Consequently, these methods are usefull for evaluation of hydrophilization of coating surfaces.View full abstractDownload PDF (1023K) -
Rie TOMITA, Satoshi URANO, Shigemi KOHIKI2001 Volume 74 Issue 9 Pages 466-471
Published: September 20, 2001
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSAn oligomer silicic ester of tetraalkoxysilane is an additive of coatings for giving hydrophilicity to the coated film surfaces. However, its mechanism of hydrophilization is not yet clear. If the mechanism is elucidated, silicic ester with a high hydrophilicity can be designed effectively and scientifically. Then, we elucidated the mechanism by the individual determination methods of the silicic ester content and the hydrolysis ratio of the surface XPS which were developed previously, and transmission electron microscope observation. Consequently, silicic ester migrated to the surface of the coated film after application of the coating containing silicic ester, form several tens nanometers layer with high silicic ester concentration and was hydrolyzed gradually with moisture in air. For a higher hydrophilic surface, it was proved that silicic was necessary to have both high migration characteristic to the surface and high hydrolyzability. As a result of examination, the higher the molecular weight was effective for higher migration characteristic and partial substitution of alkoxy groups with-I effect substituent was effective for enhancement of the hydrolyzability. Consequently, silicic ester which had higher hydrophilicity was able to be designed.View full abstractDownload PDF (1148K) -
Tsuyoshi TERADA, Toshikatsu KOBAYASHI2001 Volume 74 Issue 9 Pages 472-475
Published: September 20, 2001
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSThe effect of co-solvents on pigment dispersion in water-borne paints was evaluated. We considered that the co-solvents interfered with the stabilization by adsorption of grinding resin on the pigment, especially their hydrophobic interaction. First, we found the organic solvents used in the ordinary water-borne paints decreased the pigment dispersibility. We adopted the interfacial tension (γhsw) between water and hexane under the existence of the concerned solvent as a parameter which exhibits the degree of the interference. It was elucidated that dispersion stability was poorer when the solvent with the higher γhsw value was used.
Second, it was found this solvent effect was more enhanced when the surface tension of used pigment was higher.View full abstractDownload PDF (623K)
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