Rev. High Pressure Sci. Technol.

Vol.5  No.4(1996) Abstract

Rev. High Pressure Sci. Technol. 5-4,208-215(1996)
Effects of Compaction Pressure on Sintering Process of Poly-tetrafluoroethylene
栗山 卓  成澤 郁夫
The purpose of this article is to investigate the effect of compaction pressure on the sintering of PTFE moldings. The major factor of this process are both compaction pressure and dwell time, which lead to high compactability of moldings. Bulk density of the moldings compacted at a lower pressure increases by sintering due to coalescence of particles by viscous flow. On the other hand, there is no change of the density by sintering in higher compacted moldings, since the coalescence of particles has been already finished in the pre-forming process and sintering does not eliminate inter-particle cavities. In this case, even if the moldings are sintered in shorter times nearly at the melting temperature, their bulk density reaches a constant value.

[Poly-tetrafluoroethylene, Sintering, Compaction pressure, Bulk density, Crystallinity]
〒992 米沢市城南4-3-16 山形大学工学部物質工学科
Department of Materials Science and Engineering Yamagata University, 4-3-16 Jonan, Yonezawa 992

Rev. High Pressure Sci. Technol. 5-4,216-223(1996)
PVT Behavior of Polymers
扇澤 敏明
Pressure-Volume-Temperature(PVT)properties of polymers are very important data for polymer processing, especially, injection molding. The coefficients of thermal expansion in polymers are much larger than those of metals and inorganic materials. SO the changing of specific volumes in polymers is very large under processing, i.e., for changes of temperature and pressure. In this paper we describe the relationship between PVT behavior and processing in polymers.

[polymers, PVT behavior, polymer processing, glass transition temperature, melting point]
〒152 東京都目黒区大岡山2-12-1 東京工業大学工学部有機材料工学科
Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152

Rev. High Pressure Sci. Technol. 5-4,224-231(1996)
Measurement of Physical Properties of Polymeric Materials under High Pressure
小山 清人
Kiyohito KOYAMA
Understanding the properties of polymeric materials under high pressure is of great importance in polymer processing. This is because high pressure has a large effect on the behavior of the resin (such as flow, crystallization, compatibility, etc.) during the molding processes, and thus strongly influences the quality of the molded products. In this review, we report on measurements of the various properties of polymeric materials under high pressure which have been recently carried out. Examples include: (1)specific volume of resins under high pressure and rapid cooling rate corresponding to the actual molding conditions. (2)the pressure dependence of thermal conductivity, Young's modules and Poisson's ratio measured by modified PVT apparatus. (3)the pressure dependence of viscosity.

[polymer processing, polymeric material, high pressure, CAE, PVT, thermal conductivity, Poisson's ratio, viscosity]
〒992 米沢市城南4-3-16 山形大学工学部物質工学科
Department of Meterials Science and Engineering Yamagata University, 4-3-16 Jonan, Yonezawa 992

Rev. High Pressure Sci. Technol. 5-4,232-237(1996)
Behavior of Polymer Melt in the Mold Cavity during the Packing-Holding Process of Injection-Molding and the Effects on the Molding Failure
佐藤 勲
This article deals with the polymer behavior within the mold cavity during the packing-holding process of injection-molding from the viewpoint of pressure transmission. The packing-holding process is used to be adopted in the practical injection-molding of polymeric materials to reduce the generation of molding failure due to shrinkage of polymer melt, but sometimes the packing-holding process may induce another type of failure such as residual strain and birefringence. The author revealed the behavior of polymer melt in the mold cavity by using visualization techniques, and the reduction mechanism of molding failure due to the packing-holding process was discussed on the basis of P-V-T characteristics of the polymer material.

[injection molding, packing-holding process, visualization, molding failure, P-V-T characteristics]
〒152 目黒区大岡山2-12-1 東京工業大学工学部機械知能システム学科
Department of Mechanical and Intelligent Systems Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152

Rev. High Pressure Sci. Technol. 5-4,238-241(1996)
Effect of Pressure in Processing of Microcelullar Plastics
新保 實
Minoru SIMBO
Microcellular plastics are a unique cellular material in which voids, smaller than the natural flaw size pre-existing in polymers, are nucleated: this process results in material costs savings without significant reductions and sometimes improvements in mechanical properties. They are characterized by average cell diameter sizes on the order of 0.1 to 10μm, cell densities on the order of 109 to 1015 cells/cm3, and specific density reductions (relative to the unfoamed plastic) fyom 5 to95 percent. In this paper, the basic concept of foaming for microcellular plastics is described and the effect of pressure in processing of microcellular plastics is discussed.

[microcellular plastics, process technology, cell morphology, super-critical state, gas-polymer solution, solubility]
〒921 石川県石川郡野々市町扇ガ丘7-1 金沢工業大学 物質応用工学科
Department of Materials Science and Engineering, Kanazawa Institute of Technology, Nonoichi, Ishikawa 921

Rev. High Pressure Sci. Technol.5-4,242-247(1996)
Hydrothermal Change of Amorphous Aluminosilicate Estimated from the Heat of Immersion
渡村信治 前田雅喜 犬飼恵一 芝崎靖雄
Hydrophilicity of aluminosilicate materials is an important characteristics as an index of the degree of hydrothermal reaction and hydration of starting materials. Heat of immersion of amorphous aluminosilicate after hydrothermal treatment have been studied to clarify the meaning of the leading time of hydrothermal reaction. The heat of immersion and specific surface area are compared with structural data, XRD, DTA-TG, and IR. The hydrothermal reaction is divided into two stages:(1)hydration of amorphous aluminosilicate for the first stage and (2)crystallization of kaolinite for the second stage. The leading time of hydrothermal reaction is attributed to the hydration period o f starting material.

[ heat of immersion, amorphous aluminosilicate, hydrothermal reaction, specific surface area, kaolinite, hydrophilicity]
〒462 名古屋市北区平手町1-1 名古屋工業技術研究所
National Industrial Reaserch Institute of Nagoya, 1-1, Hirate, Kita, Nagoya 462

Rev. High Pressure Sci. Technol. 5-4,248-256(1996)
An Optical High Pressure Cell and Its Application
高野 薫
The techniques for applying an optical liquid high pressure cell are described. The optical cell described enables visual observation at high pressures up to about 1GPa. Its advantages over the diamond anvil cell are the larger sample volume, the higher accuracy of pressure measurement(about ±1 MPa), and the higher reliability of pressure control. The cell has been applied in the fields of chemistry, biology, physics, chemical engineering, and etc. Recently, we show here how it is applied to the observation of crystal growth at high pressure.

[optical cell, high pressure, crystal growth, solutions]
〒305-8573 茨城県つくば市天王台1-1-1 筑波大学物質工学系
Institute of Materials Science, University of Tsukuba, 1-1-1 Tennoudai , Tsukuba, Ibaraki 305-8573

Rev. High Pressure Sci. Technol. 5-4,257-264(1996)

Microstructure, Mechanical Properteis, and Ionic Conductivity of ZrO2-based Ceramics Fabricated by Hot Isostic Pressing
山口修1 廣田健1 稲村偉2 宮本大樹2
Special attention has been given to ZrO2-based ceramics, such as partially stabilized ZrO2(PSZ), tetragonal ZrO2 polycrystal(TZP), and ZrO2-toughened Al2O3(ZTA), to improve the mechanical properties of ceramic materials. Hot isostatic pressing(HIP) is applied to fabricate dense ZrO2-based ceramics from solid solution powders developed by sol-gel techniques. This paper reviews recent research trends and progresses related to the solid solution and composite ceramics focussing on the microstructures, strength and fracture toughness, and ionic conductivity.

[HIP, CIP, solid solution ceramics, composite ceramics]
1〒610-0321 京田辺町市多々羅都谷1-3 同志社大学工学部
Faculty of Engineering, Doshisha University, Todani 1-3, Tatara, Kyotanabe 610-0321
〒559-02 大阪府和泉市あゆみ野2-7-1 大阪府立産業技術研究所
Osaka Prefectural Institute of Industrial Technology, Ayumino2-7-1, Izumi, Osaka 559-02

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