论文部分内容阅读
The characteristics of molecular mtin of ferroelectric copolymer VDF(73)/TrFE(27) have been investigated by means of dielectric relaxation. With the rise in crystallinity. the Curie point decreases and the dielectric constant increases in the region of ferroelectric-to-paraelectric phase transition. The frequency spectra of the coplymer below room temperature consist of lowfrequency component ascribed to the micro-Brownian motions of molecular segments in the noncrystalline regins and high-frequency cmponent associated with the local motions of smallscale segments. By using the fitting results with one or two Cole-Cole functions, and calculating with WLF equation and Arrhenius formula, the glass transition temperature and the activation energy of local relaxation are obtained. the distribution of relaxation time in the molten and ferroelectric phases is located at a same line, and complies with Arrhenius ruIe, which suggests that the elementary motions are of same type for molecular motions provided by the hightemperature process and the low-temperature local mode process
The characteristics of molecular mtin of ferroelectric copolymer VDF (73) / TrFE (27) have been investigated by means of dielectric relaxation. With the rise in crystallinity. The Curie point decreases and the dielectric constant increases in the region of ferroelectric-to-paraelectric phase transition. The frequency spectra of the coplymer below room temperature consist of low frequency components ascribed to the micro-Brownian motions of molecular segments in the noncrystalline regins and high-frequency cmponent associated with the local motions of small scale segments. one or two Cole-Cole functions, and calculated with WLF equation and Arrhenius formula, the glass transition temperature and the activation energy of local relaxation are obtained. the distribution of relaxation time in the molten and ferroelectric phases is located at a same line, and complies with Arrhenius ruIe, which suggests that the elementary motions are of the same type for molecular mo tions provided by the high temperature process and the low-temperature local mode process