Dielectric relaxations and electrical conductivities of poly(alkyl methacrylates) under high pressure
Dielectric relaxations and electrical conductivities of poly(alkyl methacrylates) under high pressure
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高压下聚甲基丙烯酸烷基酯的介电弛豫和电导率
DOI：
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发表时间：
1968
期刊：
影响因子：
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通讯作者：
S. Saitō
中科院分区：
文献类型：
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作者：
H. Sasabe;S. Saitō
研究了四种甲基丙烯酸酯聚合物(甲基、乙基、正丁基和正辛基)在0.0001 cps-300kcps的频率范围内、玻璃化转变温度上下的温度和高达2500atm的不同压力下的介电性能。在远高于Tg的温度下，对于较高的甲基丙烯酸烷基酯，观察到一个单一的弛豫峰(α峰)。然而，随着温度的降低或压力的增加，这一峰被分成两个峰，α和β。与α和β驰豫过程相对应的分子运动分别是无定形主链的微布朗运动和柔性侧链的微布朗运动。从这些聚合物的平均介电松弛时间与温度和压力的关系来看，单一松弛过程(α过程)可归结为主链和侧链的微布朗运动耦合。温度和压力对直流的影响。还研究了这些聚合物的导电性。
Dielectric properties of four methacrylate polymers (methyl, ethyl, n-butyl and n-octyl) were studied in the frequency range 0.0001 cps–300 kcps at temperatures above and below the glass transition temperature and at various pressures up to 2500 atm. At temperatures well above Tg a single relaxation peak (α′ peak) was observed in the case of the higher n-alkyl methacrylates. However, this peak was split into two peaks, α and β, with decrease in temperature or increase in pressure. The molecular motions corresponding to the α and the β relaxation processes are the micro-Brownian motions of amorphous main chains and of flexible side chains, respectively. From the temperature and the pressure dependence of the average dielectric relaxation time of these polymers the single relaxation process (the α′ process) was attributed to the micro-Brownian motion of the main chain coupled with that of the side chain. The effects of temperature and pressure on the d.c. conductivity of these polymers were also studied.