两种典型星用聚合物介质抗内带电改性防护技术研究

STUDY ON THE DEEP DIELECTRIC CHARGING PROTECTION TECHNOLOGY OF TWO TYPICAL POLYMERS ON SPACECRAFT

空间高能电子辐射易造成星用聚合物介质内带电水平过高,是卫星运行可靠性的潜在威胁因素。对航天器介质材料进行非线性电导改性是提高航天器介质材料自释电荷能力,进而降低内带电水平的有效方法。实验选用半导电无机添加剂对典型空间聚合物材料聚四氟乙烯、聚酰亚胺进行改性工艺和电导特性研究,测量了常态体电导率与添加剂含量关系,不同含量添加剂下复合材料体电导率随温度与电场的变化规律以及复合材料的导热性能参数。实验表明,添加剂含量会显著影响复合材料的体电导特性及导热特性,特别是复合材料的非线性电导特性阈值电场降低最为明显。这种既能保持高绝缘性能又具有良好非线性电导特性的新型复合介质材料,有希望成为从根本上解决星用聚合物介质深层带电问题的有效措施。

The high-energy electron radiation can easily lead to the high level of deep dielectric charging in spacecraft used polymers,which is the potential threat to the operation of spacecraft.The conduction modification is an effective method to raise the charge releasing ability of the material and lower down the level of deep dielectric charging.A kind of semi-conductive inorganic filler is doped into the two typical spacecraft polymers,polytetrafluoroethylene（PTFE） and polyimide（PI）,and the processing technology and conduction properties of the composites were studied.The normal state conductivity,the temperature-dependent conduction property,the nonlinear conduction property and the thermal conductivity of the composites with different filler contents were measured.The experimental results indicate that,the electrical conduction and the thermal conduction are both influenced by the inorganic filler,especially the threshold field of the nonlinear conduction property drops obviously.The composites,possessing the high insulation and nonlinear conduction property,may solve the deep dielectric charging phenomenon of the spacecraft polymers.