Li Zhongyuan, Zhao Hong, Zhang Changhai
Key Laboratory of Engineering Dielectric and its Application, Ministry of Education, College of Electrical and Electronics Engineering, Harbin University of Science and Technology, Harbin 150040, China.
College of Science, Harbin University of Science and Technology, Harbin 150040, China.
Materials (Basel). 2018 Sep 2;11(9):1590. doi: 10.3390/ma11091590.
Researches of the theories and application of polymer composites with nonlinear conductivity are useful for dealing with the nonuniform electrical fields widely existing in the cable accessory insulation. In the present work, we fabricated CCTO (CaCu₃Ti₄O)/EPDM (Ethylene Propylene Diene Monomer) composites and investigated their breakdown strength, dielectric and nonlinear conductivity properties in detail; the microstructures of fillers and composites were characterized by scanning electron microscopy (SEM) and X-ray diffraction. CCTO particles are uniformly dispersed in CCTO/EPDM composites, and the composites showed nonlinear conductivity with electric field changes. When the CCTO particle content is low, the conductivity of CCTO/EPDM composites does not present obvious nonlinearity. However, when CCTO content exceeds 2 vol %, the conductivity experiences a nonlinear change with increasing electric field strength and the threshold field (E) of nonlinear conductivity declines with the increase of CCTO contents. In addition, it can be found from experiment and simulation results that 8 vol % CCTO/EPDM exhibit significant nonlinear conductivity and dielectric properties as expected, and homogenizing the electrical field much more effectively. Therefore, this paper offers a preliminary discussion about the variation trend of nonlinear conductivity CCTO/EDPM composites, providing an effective reference to solve the application of nonlinear conductivity materials for cable accessories.
具有非线性导电性能的聚合物复合材料的理论与应用研究，对于处理电缆附件绝缘中广泛存在的非均匀电场很有帮助。在本工作中，我们制备了CCTO（CaCu₃Ti₄O）/EPDM（乙丙三元橡胶）复合材料，并详细研究了它们的击穿强度、介电性能和非线性导电性能；通过扫描电子显微镜（SEM）和X射线衍射对填料和复合材料的微观结构进行了表征。CCTO颗粒均匀分散在CCTO/EPDM复合材料中，复合材料的导电率随电场变化呈现非线性。当CCTO颗粒含量较低时，CCTO/EPDM复合材料的导电率没有明显的非线性。然而，当CCTO含量超过2体积%时，导电率随电场强度增加呈非线性变化，且非线性导电的阈值场（E）随CCTO含量的增加而降低。此外，从实验和模拟结果可以发现，8体积%的CCTO/EPDM如预期表现出显著的非线性导电和介电性能，并且能更有效地使电场均匀化。因此，本文对CCTO/EDPM复合材料非线性导电率的变化趋势进行了初步探讨，为解决非线性导电材料在电缆附件中的应用提供了有效的参考。
