Journal of the Society of Powder Technology, Japan

Microstructure and Frost Durability of Vinylon Fibers-reinforced Building Materials using Globular Cement

Sadashi TANIGUCHI, Masahiko NAKAMURA

1996 Volume 33 Issue 8 Pages 624-631
Published: August 10, 1996
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.33.624

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Building material samples were made by using a nonasbestos fiber-reinforced globular cement composite material treated with a high-velocity pneumatic double-stage impactor. The effects that the different mixing methods the modifying mechanism exerted on the process of changing specific surface area, the pore size distribution before and after freeze-thaw cyces of the building material, the improvement of the microstructure, the frost durability and the heightening of the strength were examined.
As the results, the following improvement in the characteristics was obtained. The correlation between the fractal dimension D_F of the range of pore size of 0.01-1μm and frost damage property was obtained. It was found that the reduction of the minimum water/cement ratio at kneading and forming are feasible by the treatment of becoming globular. The lowering of D_F and the improvement of the frost durability can be obtained.
In the system being treated with the process of becoming globular, the total pore volume decreased. The proportion of the pore volume in the zone of 0.05-1.0μm pore size which adjoins the zone of 0.01-0.05μm corresponding to the pores inside reinforcing fiber bundle was relatively large. Consequently, the channels for flowing water at the time of freezing were secured, and the improvement of the frost durability was obtained.

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Preparation by Spray Drying of Microcapsules with a Core of a Water Soluble Substace and a Shell of Ethylcellulose

Noriyuki YAMADA, Hiroyuki NAKAMURA, Eiichi ABE

1996 Volume 33 Issue 8 Pages 632-637
Published: August 10, 1996
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.33.632

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An attempt was made to produce microcapsules with cores of a water soluble substance and shells of ethylcellulose by spray drying. Core particles were first prepared by spray drying the mixed suspension of a water soluble substance, i. e., brilliant blue, and gelatine as a matrix base. The core particles smaller than 74μm, treated with titanium stearate, were subsequently suspended in a solution of 2-propanol, water, lethitin and ethylcellulose. Mono-core and multi-core microcapsules were obtained by spray drying the suspension. The addition of water to the solution resulted in promoting the evaporation rate of the droplets due to delaying the film formation of ethylcellulose during drying. Mono-core microcapsules of 44 to 74μm a proved to show a maximum 50% release time of 60minutes.

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The Effectiveness of Inorganic Compounds on the Improvement of the Compressibility in the Crude Drug Tablets

Mitsuhiro SOFUE, Yoshinori UEDA

1996 Volume 33 Issue 8 Pages 638-642
Published: August 10, 1996
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.33.638

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It is generally recognized that most crude drugs have less compressibility, Although crystalline cellulose which has been developed for the direct compression method is widely used to improve compressibility, it has not been expected to improve the compressibility of crude drugs. We therefore try to improve and evaluate compressibility with synthetic aluminum silicate and synthetic hydrotalcite, which are inorganic compounds and have higher compressibility in themselves.
The compressibility was improved in a dosage-dependent manner, by adding these inorganic compounds to the crude drugs. This mechanism has not been definitely clarified. In the present study, the higher compressibility and the particle size of the pharmaceutical exipients might be related to the compressibility of the crude drug and to these inorganic compounds which have the effect of reducing the elasticity of a crude drug.

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The Characteristics of Fine Granules and Evaluation of their Dispensing Characteristics

Moriyuki OHKUMA, Keiko OHTSUKI, Takayasu ISHIKAWA, Atsushi OH'ISHI, Ke ...

1996 Volume 33 Issue 8 Pages 643-648
Published: August 10, 1996
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.33.643

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The object of this research is to determine the relationship between the characteristics and dispensing of fine granules, as well as the establishment of the formulation design for the manufacturing of fine granules suitable for dispensing.
Fine granules were prepared by a high speed agitating granulator based on “the Standard Formula for Fine Granules” established by the Standard Formulation Research Association, the Particulate Preparation and Design Group, the Society of Technology, Japan.
The Carr's Fluidity index was applied to evaluate the characteristics of fine granules, and evaluation of the dispensing characteristics was done in the same manner as in our previous papery.
The results of this study were that, it was observed that the fine granules, which were good for the dispensing characteristics, showed a Carr's fluidity index of about 80 (good-very good). It was found that the fine granules which had high yields showed both good fluidity and good dispensing properties.

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AC Corona Charging Behavior of Polymer Powder Layers of Various Particle Sizes

Chiseki YAMAGUCHI, Tau OU, Fujio KANEKO, Manabu TAKEUCHI

1996 Volume 33 Issue 8 Pages 649-654
Published: August 10, 1996
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.33.649

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The behavior of charges in polymer powder layers charged by an alternating current (AC) corona discharge were examined by surface potential measurements and the separation of powder layer by applying an electrical field. A commercial epoxy-polyester paint powder was used as the sample polymer powder in this study. The relationship between the surface potential of the powder layers of various particle sizes and charge distributions within the powder layers was studied. The surface potential of the powder layer consisting of small-sized particles was higher than that of the powder layer consisting of large-sized particles. This result was attributable to the difference in charge distribution within the powder layers which was caused by the total surface area of the powder layer. The charge distribution within the powder layer and the surface potential decay rate depended on the AC corona discharge conditions for the large particle-sized powder layer. The surface potential decay rate changed with the fraction of the large particle-sized particles in the powder layer.

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Development of Polymer Fine Particles and Surface Modification for Powder Materials

Tatsuhiro IMAI, Susumu KAWASE

1996 Volume 33 Issue 8 Pages 655-663
Published: August 10, 1996
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.33.655

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[title in Japanese]

Kanji MATSUMOTO

1996 Volume 33 Issue 8 Pages 670-675
Published: August 10, 1996
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.33.670

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[title in Japanese]

Satoru WATANO

1996 Volume 33 Issue 8 Pages 676-678
Published: August 10, 1996
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.33.676

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Erratum to : Improvement of Surface Treatment and Blending of Milk Casein with Titanium Oxide

1996 Volume 33 Issue 8 Pages 694
Published: 1996
Released on J-STAGE: April 30, 2010

DOIhttps://doi.org/10.4164/sptj.33.8_694

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