微纳米SiO2/低密度聚乙烯复合材料的空间电荷性能

Space charge properties of micro and nano SiO2/low density polyethylene composites

高压直流绝缘材料中空间电荷积聚限制了直流输电的发展。为探讨微米SiO2、纳米SiO2、微纳米SiO2及制备工艺对SiO2/低密度聚乙烯(LDPE)复合材料空间电荷特性的影响。分别利用SEM、FTIR和DSC等对不同SiO2/LDPE复合材料的微结构、结晶特性等进行了表征,利用热刺激电流(TSC)法研究其陷阱特性,通过电声脉冲(PEA)法研究其空间电荷特性。结果表明:SiO2的引入使LDPE的晶粒尺寸减小,结晶度提高;SiO2/LDPE复合材料的TSC曲线所包络面积增大,微米SiO2的引入使TSC峰向低温方向偏移,而纳米SiO2的引入使TSC峰向高温方向移动;SiO2/LDPE复合材料表现出对空间电荷不同程度的抑制作用。微纳米SiO2/LDPE复合材料的制备工艺对其性能有一定的影响,以母料形式制备微纳米SiO2/LDPE复合材料时,其性能与后加入无机颗粒对应的SiO2/LDPE复合材料更接近。

The development of high voltage direct current(HVDC)transmission is limited on account of the space charge accumulation in HVDC insulation.The effects of nano SiO2,micro SiO2,micro and nano SiO2and the preparation process on the space charge behavior in SiO2/low density polyethylene(LDPE)composites were investigated.The microstructure and crystallization characteristics of different SiO2/LDPE composites were characterized by SEM,FTIR and DSC.The trap characteristics of SiO2/LDPE composites were studied using thermally stimulated current(TSC).The space charge behavior in the pure LDPE and SiO2/LDPE composites were investigated by electro-acoustic pulse(PEA)technique.The results show that the grain size of LDPE is reduced by the introduction of SiO2,and the crystallinity is increased.The area under TSC curves of SiO2/LDPE composites increases,the TSC peaks of micro SiO2/LDPE composites shift to lower temperature,and those of SiO2/LDPE composites with nano SiO2 move higher temperature.All SiO2/LDPE composites exhibit the effect inhibiting space charge to some extent.The preparation process of micro and nano SiO2/LDPE composite has certain influence on its performance.When the micro and nano SiO2/LDPE composite is prepared in the form of masterbatch,its performance is closer to the composite corresponding to the inorganic particles added later.