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首页> 外文期刊>Journal of Physics, D. Applied Physics: A Europhysics Journal >Comparative study of Poly(n-butyl methacrylate) by thermo-stimulated currents and dynamic dielectric spectroscopy
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Comparative study of Poly(n-butyl methacrylate) by thermo-stimulated currents and dynamic dielectric spectroscopy

机译：聚甲基丙烯酸正丁酯的热激励电流和动态介电谱的比较研究

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The dielectric behaviour of Poly(n-butyl methacrylate) (PnBMA) has been studied by thermo-stimulated currents (TSC) and dynamic dielectric spectroscopy (DDS). The analysis of the TSC complex spectrum shows the existence of three dipolar relaxations around the glass transition. The first one, labelled beta, near -25degreesC, has been assigned to a secondary relaxation mode. The second one, alpha, at 30degreesC, has been associated with the glass relaxation. The third one, above T-g at 90degreesC, might be assigned to the dielectric manifestation of the liquid-liquid transition. The use of fractional polarizations allows us to determine the fine structure of these three modes. The relaxation times of the beta and alpha modes are widely distributed and they follow an Arrhenius equation. We also report a compensation phenomenon for the alpha mode. As for the alpha' mode, the relaxation times are narrowly distributed and they obey a Vogel equation. By using a blocking electrode, the study by DDS exhibits three relaxational phenomena: the beta and alpha modes which merge approximately at 10(4) Hz and lead to an (alphabeta) mode, and an additional alpha' phenomenon. By using the Havriliak-Negami parameters, we characterize the shift of their maxima with frequency and temperature. The consistent set of data obtained from TSC and DDS allows us to follow the relaxation modes of PnBMA in a very broad temperature and frequency range. They significantly improve the knowledge of molecular mobility/dynamic structure relationships. [References: 10]
机译：聚甲基丙烯酸正丁酯（PnBMA）的介电行为已通过热激励电流（TSC）和动态介电谱（DDS）进行了研究。 TSC复光谱的分析表明，在玻璃化转变附近存在三个偶极弛豫。第一个标记为β的-25°C附近的温度已分配给第二弛豫模式。第二个温度是30摄氏度，与玻璃松弛有关。在90°C时，T-g以上的第三个可能被归因于液-液转变的介电表现。分数极化的使用使我们能够确定这三种模式的精细结构。 beta和alpha模式的弛豫时间分布广泛，并且遵循Arrhenius方程。我们还报告了alpha模式的补偿现象。至于α'模式，弛豫时间分布狭窄，并且服从沃格尔方程。通过使用阻挡电极，DDS的研究显示出三种弛豫现象：β模式和α模式大约在10（4）Hz合并并导致（αbeta）模式，另外还有一种alpha'现象。通过使用Havriliak-Negami参数，我们可以表征其最大值随频率和温度的变化。从TSC和DDS获得的一致数据集使我们能够在非常宽的温度和频率范围内遵循PnBMA的弛豫模式。它们显着提高了分子迁移率/动力学结构关系的知识。 [参考：10]

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