钛酸铜钙-氮化硼掺杂EPDM复合介质的电学和力学性能研究

非线性电导材料的应用是解决高压直流电缆附件内部电场集中问题的一种有效方案.因此,通过掺杂钛酸铜钙(calcium copper titanate,CCTO)纳米填料对三元乙丙橡胶(ethylene-propylene-diene monomer,EPDM)进行改性,在较低的掺杂体积分数(2％CCTO)下,复合介质展现出...

Study on Electrical and Mechanical Properties of Calcium Copper Titanate boron Nitride Doped EPDM Composites

The application of nonlinear conductivity materials is an effective solution to solve the problem of electric field concentration in HVDC cable accessories. In this paper, ethylene-propylene-diene monomer(EPDM) is modified by doping calcium copper titanate(CCTO) nanofiller. When the doping content is lower(2% CCTO), the composite exhibits better nonlinear conductivity. When the CCTO volume fraction reaches 10%, the nonlinear coefficient will reach 5.40. Simultaneously, the breakdown field strength of the composites with a higher CCTO content is severely degraded. Based on this phenomenon, hexagonal boron nitride(BN) with good insulation and excellent thermal conductivity is employed to dope into EPDM matrix. The breakdown field strength of the co-doped composites is significantly improved, and the characteristic breakdown field strength when φ=10%CCTO/ω=9%BN/EPDM increases to 90.1 kV/mm(φ is volume fraction, ω is mass fraction), which is 35.9% higher than that of 10%CCTO/EPDM composites(66.3 kV/mm), simultaneously, the co-doped composites exhibit obvious nonlinear conductivity. In addition, this paper discusses the effect of temperature on the nonlinear conductivity and breakdown characteristics of the composites. The mechanical properties of single-doped and co-doped composites are tested and analyzed. The results show that the doping of two kinds of inorganic fillers can improve the mechanical properties of EPDM, and the tensile strength and tensile elongation of composites increase gradually with the increase of CCTO doping content.