伽玛线辐射对LDPE表面电导率的影响.doc


伽玛线辐射对 LDPE 表面电导率的影响#
高宇,门业堃,杜伯学*
(天津大学电气与自动化工程学院,天津 300072)
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摘要:应用于核电站、宇宙航天器等辐射环境中的聚乙烯绝缘材料因表面电荷积聚而易于引
发放电事故,掌握高能辐射对聚乙烯表面电导率的影响规律对抑制表面电荷积聚、保障核设
施绝缘安全具有重要意义。选取厚 2 mm 的低密度聚乙烯薄板为试样,采用 60Co 伽玛射线
源以 10 kGy/h 的辐射率对其进行辐射,总辐射量分别为 100 kGy 和 1000 kGy。基于三电极
法测量不同相对湿度下试样的表面电导率,结合衰减全反射傅立叶变换红外光谱和凝胶含
量,分析总辐射量的影响。结果表明:表面电导率随总辐射量的增加而增大;随相对湿度从
45%增大至 75%,表面电导率增大约 5 个数量级。论文认为,伽玛线辐射引发的氧化反应使
低密度聚乙烯表层形成羰基,可作为浅能级载流子陷阱或吸附水分子,促进电荷迁移,从而
导致表面电导率提高。
关键词:绝缘技术;低密度聚乙烯;表面电导率;伽玛线辐射;衰减全反射傅立叶变换红外
光谱;凝胶含量
中图分类号:TM852
Effect of gamma-ray irradiation on surface conductivity of
LDPE
GAO Yu, MEN Yekun, DU Boxue
(School of Electrical Engineering and Automation, Tianjin University,Tianjin 300072)
Abstract: In this work, the effect of gamma-ray irradiation on surface conductivity of LDPE has
been investigated. The sample was previously irradiated at room temperature in air to 100 kGy
and then to 1000 kGy with a dose rate of 10 kGy / h by using a 60Co gamma-source. Surface
conductivity was measured by means of an insulation resistance meter (Model PC 68) at various
relative humidity. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectrum
and gel fraction were utilized to estimate the change in molecular structure of LDPE. Obtained
results show that the surface conductivity tends to increase with the growth of the total dose. An
increase in t