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为探讨纳米ZnO/低密度聚乙烯(LDPE)复合材料的介电特性,首先,采用硅烷偶联剂和钛酸酯偶联剂对纳米ZnO进行改性,并利用两步法制备了不同纳米ZnO质量分数、不同纳米ZnO粒径、不同纳米ZnO表面修饰方式和不同冷却方式的纳米ZnO/LDPE复合材料;然后,通过FTIR、SEM、DSC和热激电流(TSC)测试了纳米ZnO在基体中的分散情况、复合材料的等温结晶过程参数变化及陷阱密度;最后,在不同实验温度下分别进行了交流击穿、绝缘电导率、介电常数和空间电荷实验。结果表明:纳米ZnO的加入使纳米ZnO/LDPE复合材料内部陷阱深度和密度均有所增加;当纳米ZnO的粒径为40nm且质量分数为3%时,复合材料的结晶速度最快,纳米ZnO在基体中的分散性较好,击穿场强达到最高值133.3kV/mm,电导率及介电常数也相对较低,加压时复合材料内部空间电荷少,短路时释放电荷速度快,介电性能较好;由于纳米粒子增加了材料内部的热传导速率,降低了复合材料随着温度升高而降解的速度,因而相对于纯LDPE,随着实验温度的提高,纳米ZnO/LDPE复合材料的击穿场强下降幅度及电导率上升幅度均较小。
In order to investigate the dielectric properties of nano-ZnO / LDPE composites, firstly, the nano-ZnO was modified by silane coupling agent and titanate coupling agent, and the nano-ZnO Nano ZnO / LDPE composite with different nano-ZnO surface modification methods and different cooling methods were prepared. Then the nano ZnO / LDPE composites were tested by FTIR, SEM, DSC and heat shock current (TSC) Dispersion, the change of isothermal crystallization process parameters and the trap density of the composites. Finally, AC breakdown, insulation conductivity, dielectric constant and space charge experiments were carried out at different experimental temperatures. The results show that the depth and density of traps in nano-ZnO / LDPE composites increase with the addition of nano-ZnO. When the particle size of nano-ZnO is 40nm and the mass fraction is 3%, the crystallization rate of nano- In the matrix, the dispersion is better, the breakdown field reaches the highest value of 133.3kV / mm, the conductivity and dielectric constant are relatively low, and the charge in the composite is less in the space and the charge is released faster in the short circuit. The electrical properties are better; as the nano-particles increase the heat conduction rate inside the material and reduce the degradation rate of the composite material with increasing temperature, compared with the pure LDPE, with the increase of the experimental temperature, the nano-ZnO / LDPE composites Breakdown of field strength decreased and the conductivity increase rate is small.