Electrical/dielectric properties and conduction mechanism in melt processed polyamide/multi-walled carbon nanotubes composites
Electrical/dielectric properties and conduction mechanism in melt processed polyamide/multi-walled carbon nanotubes composites
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DOI：
10.1016/j.polymer.2009.08.038
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发表时间：
2009-10-09
期刊：
影响因子：
4.6
通讯作者：
Omastova, M.
中科院分区：
文献类型：
--
作者：
Logakis, E.;Pandis, Ch.;Omastova, M.
采用介电弛豫光谱在宽频率（10（-2）-10（6）Hz）和温度范围（-150至150℃）内研究了熔融混合制备的聚酰胺6（PA6）/多壁碳纳米管（MWCNT）纳米复合材料的电学和介电性能。透射电子显微镜显示碳纳米管在聚合物基体中的分散状态良好。通过使用直流电导率和从直流到交流转变的临界频率 (f(c)) 对 MWCNT 中体积％浓度的依赖性，发现逾渗阈值 (p(c)) 为 1.7 体积％。使用理论模型（由 Garboczi 等人提出）计算纳米复合材料中纳米管的实际长径比，并根据排除体积理论将所得值与 p(c) 值相关。此外，发现导电纳米管之间的接触电阻 (R-c) 类似于 10(5) Ω。对电导率温度依赖性的研究揭示了电荷传输是由热波动引起的隧道效应控制的，温度高达玻璃化转变。最后表明，纳米管的添加对PA6基体的弛豫机制没有显着影响。 (C) 2009 Elsevier Ltd. 保留所有权利。
The electrical and dielectric properties of polyamide 6 (PA6)/multi-walled carbon nanotubes (MWCNT) nanocomposites prepared by melt mixing were investigated by employing dielectric relaxation spectroscopy in broad frequency (10(-2)-10(6) Hz) and temperature ranges (from -150 to 150 degrees C). Transmission electron microscopy revealed a good state of CNT dispersion in the polymeric matrix. The percolation threshold (p(c)) was found to be 1.7 vol.% by using the dependence of both dc conductivity and critical frequency (f(c)) from dc to ac transition on vol.% concentration in MWCNT. The actual aspect ratio of the nanotubes in the nanocomposites was calculated using a theoretical model (proposed by Garboczi et al.) and the obtained value was correlated with the p(c) value according to the excluded volume theory. Additionally, the contact resistance (R-c) between the conductive nanotubes was found to be similar to 10(5) Omega. Investigation of the temperature dependence of conductivity revealed a charge transport which is controlled by thermal fluctuation-induced tunneling for temperatures up to the glass transition. Finally, it was shown that the addition of nanotubes has no significant influence on the relaxation mechanisms of the PA6 matrix. (C) 2009 Elsevier Ltd. All rights reserved.