中国物理B ›› 1994, Vol. 3 ›› Issue (5): 374-383.doi: 10.1088/1004-423X/3/5/008

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LOW-TEMPERATURE LOW-FREQUENCY DIELECTRIC RELAXATIONS IN VDF(81)/TeFE(19) COPOLYMERS

TAKEO FURUKAWA1, 张兴元2   

  1. (1)Department of Chemistry, Science University of Tokyo, 162 Japan; (2)Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
  • 收稿日期:1993-04-07 出版日期:1994-05-20 发布日期:1994-05-20

LOW-TEMPERATURE LOW-FREQUENCY DIELECTRIC RELAXATIONS IN VDF(81)/TeFE(19) COPOLYMERS

ZHANG XING-YUAN(张兴元)a, TAKEO FURUKAWAb   

  1. a Department of Chemistry, Science University of Tokyo, 162 Japan; b Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
  • Received:1993-04-07 Online:1994-05-20 Published:1994-05-20

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摘要： The complex dielectric constants of ferroelectric copolymers VDF(81)/TeFE(19) with dif-ferent crystallinities have been measured over the range of-120- +40℃ and 10-2-10-4 Hz, using an improved dielectric relaxation spectrometer. The low-temperature processes of di-electric relaxation show that the frequency spectra of copolymers below room temperature consist of two parts: a low-frequency component which accords with a WLF equation and is ascribed to the micro-Brownian motions of frozen-in segments in the noncrystalline regions, and a high-frequency component which follows an Arrhenius rule and is designated as the local motions of small-scale segments in the crystalline and/or noncrystalline regions. The calculated results indicate that Tg of copolymers is -52℃ and the activation energy of local relaxation is 37.7 kJ/mol.

Abstract: The complex dielectric constants of ferroelectric copolymers VDF(81)/TeFE(19) with dif-ferent crystallinities have been measured over the range of-120- +40℃ and 10-2-10-4 Hz, using an improved dielectric relaxation spectrometer. The low-temperature processes of di-electric relaxation show that the frequency spectra of copolymers below room temperature consist of two parts: a low-frequency component which accords with a WLF equation and is ascribed to the micro-Brownian motions of frozen-in segments in the noncrystalline regions, and a high-frequency component which follows an Arrhenius rule and is designated as the local motions of small-scale segments in the crystalline and/or noncrystalline regions. The calculated results indicate that Tg of copolymers is -52℃ and the activation energy of local relaxation is 37.7 kJ/mol.

中图分类号:  (Dielectric loss and relaxation)

  • 77.22.Gm
77.22.Ch (Permittivity (dielectric function)) 77.84.Jd (Polymers; organic compounds) 82.35.Jk (Copolymers, phase transitions, structure) 72.30.+q (High-frequency effects; plasma effects)