硅橡胶绝缘介质的分子链运动与电极极化特性  

Molecular Chain Motion and Electrode Polarization Properties of Silicone Rubber

作　　者：康文斌[1] 蒙绍兴 李世军 闵道敏[2] 李枕 李盛涛[2] KANG Wenbin;MENG Shaoxing;LI Shijun;MIN Daomin;LI Zhen;LI Shengtao(China Electric Power Research Insutitute,Wuhan 430074,China;State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Xi'an 710049,China)

机构地区：[1]中国电力科学研究院,武汉430074 [2]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《高电压技术》2018年第12期3798-3807,共10页High Voltage Engineering

基　　金：国家电网公司科技项目(EPRIGYKJ(2015)4268)~~

摘　　要：硅橡胶材料具有优良的电学特性,其介电性能受到分子链运动和电极极化特性的影响。文中首先利用红外光谱和X射线光电子能谱对硅橡胶材料的分子基团和元素进行分析,利用差式扫描量热仪测试出硅橡胶材料的玻璃化转变温度为-123℃。其次,利用宽带介电谱仪测试硅橡胶材料在不同温度下的介电性能。实验结果发现,硅橡胶在高频范围内存在由分子链段运动导致的介电松弛过程α和δ,在低频范围内存在离子迁移导致的直流电导过程,并且在高温条件(140-200℃)下,还存在明显的电极极化过程。硅橡胶分子介电松弛过程α、δ服从Cole-Davidson公式,通过拟合计算,发现松弛过程α、δ的松弛时间常数与温度的关系服从Arrhenius公式,其活化能分别为0.10eV和0.14eV,并得到了两个松弛过程在不同温度下的介电松弛强度和介电松弛时间分布特性。利用Macdonald模型分析硅橡胶材料电极极化过程,计算得到可动离子浓度,以及在不同温度下的德拜长度、可动离子迁移率和扩散率等参数,发现可动离子迁移率随温度的变化关系服从Arrhenius公式,并计算得到活化能为0.38eV。最后通过硅橡胶热刺激电流实验验证了硅橡胶材料中存在松弛过程α、δ和电极极化过程。Silicone rubber (SiR) possesses outstanding electrical characteristics, and its dielectric properties are easily affected by molecular chain motion and electrode polarization. We employed infrared spectroscopy and X-ray photoelectron spectroscopy to analyze the functional group and element in SiR specimen. Then, the glass-transition temperature was measured as a value of -123 ℃ owing to different scanning calorimetry (DSC). Frequency domain spectroscopy (FDS) was applied to detect the dielectric relaxation process in SiR at different temperatures. According to the FDS results the relaxation process α & δ caused by molecular chain motion could be observed on a high-frequency domain, while the DC conductivity induced by ion drift appeared on a low-frequency domain, particularly, an electrode polarization process appeared apparently on low frequency domain at high temperatures (140-200 ℃). The relaxation process α & δ caused by molecular chain motion followed the Cole-Davidson relaxation function, based on which the dielectric relaxation intensity and relaxation time distribution at different temperatures were calculated. Besides, the relaxation time constant of relaxation process α & δ as a function of reciprocal temperature obeyed the Arrhenius equation, with an activation energy of 0.10 eV and 0.14 eV respectively. Then, according to the Macdonald model, the polarization electrode process in SiR was analyzed, and corresponding parameters such as the free ion density, Debye length, free ion mobility, and diffusivity at different temperatures were obtained. The temperature dependency of free ion mobility obeyed the Arrhenius equation, with an activation energy of 0.39 eV. At last, the thermal stimulated depolarization current (TSDC) was applied to confirm the existence of relaxation process α & δ and electrode polarization.

关 键 词：硅橡胶 介电响应 分子链运动 电极极化 频域介电谱 热刺激电流 

分 类 号：TM215.2[一般工业技术—材料科学与工程]