| Project/Area Number |
04555212
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
高分子物性・高分子材料（含機械材料）
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| Research Institution | Yamagata University |
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Principal Investigator |
OHIGASHI Hiroji Yamagata University, Faculty of Engineering, Department of Materals Science & Technology, Professor, 工学部, 教授 (90185372)
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| Co-Investigator(Kenkyū-buntansha) |
AKAMA Shuyo Central Glass Co.Ltd, Tokyo Research Laboratories, Senior Research Chemist., 東京研究所, 研究員
HIKOSAKA Masamichi Yamagata University,, 工学部, 助教授 (60087103)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥11,300,000 (Direct Cost: ¥11,300,000)
Fiscal Year 1993: ¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1992: ¥5,600,000 (Direct Cost: ¥5,600,000)
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| Keywords | Piezoelectric Polymer / Ferroelectric Polymer / Thermo-Stable Piezoelectricity / PVDF / High Pressure / Crystallization / Ultrasonic Transducer / Copolymer of VDF / 高分子圧電材料 / 圧電性 / PVDF / P(VDF-TrFE) / フッ素系高分子 / すべり弾性率 / えべり拡散 |
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| Research Abstract |
This research project was performed for development of new piezoelectricpolymer materials having the electromechanical coupling factor kt more than 0.25 and durable for use under high-temperature ambient condition. Crystallization of poly ( vinylidene-fluoride ) in the hexagonal phase, which appears only at highpressure and temperatures, yielded a film comprizing extended chain lamellar crystals of the beta-form crystal structure. The resulting film has a kt value of 0.27, and retains its piezoelectric activityup to the temperatures just below the melting point, 205ﾟC.High-pressure crystallized PVDF film thus much improved piezoelectric properties as compared to convential PVDF,which has a kt value of 0.2, and loses its activity at 120ﾟC.The usefulness of the newly developed PVDF film as an ultrasonic transducer material working at the megahertz frequency range was demonstrated by constructing ultrasonic transducers which operated effectively at 180-200ﾟC.
In addition to the above mentioned results, we have many additional results important both technologically and scientifically. Some of them are as follows :
( 1 ) Pressure dependence of Curie temperature and melting point for PVDFand P ( VDF-TrFE ) ( VDF Trifluoroethylenecopolymers ) was determined.
( 2 ) Ferroelectic domain structure in a single crystal lamellae of P ( VDF-TrFE ) was first observed by TEM.
( 3 ) Anisotropic motion of chainmolecules in a single crystalline lamella of P ( VDF-TrFE ) was detected by usingAT-cut quartz resonators ; the moleculesin the paraelectric phase are very mobilealong the direction parallel to the chain axis like liquid, while they are ridgid for the shear stress across the chainaxis.
( 4 ) Highly-doublly-oriented films ( single crystal like films ) of P (VDF-TrFE ) were found to be fabricated by a special treatment techmique.
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