超支化聚酯改性纳米BN/TiO₂环氧树脂的电气特性研究

Effect of Hyperbranched Polyester Grafting Nano Boron Nitride/Nano Titanium Dioxide on Electrical Characteristics of Epoxy Resin

摘要: 为研究BN/TiO₂填充环氧树脂复合材料的介电性能和绝缘性能，制备了不同填充量和混合比例的BN/TiO₂环氧树脂复合材料，并分别测试了其介质损耗因数、介电常数、体积电阻率、表面电阻率、局部放电起始电场强度及交流击穿场强，研究了超支化CHBP处理对复合材料介电性能和绝缘性能的影响。研究发现CHBP处理后BN:TiO₂ (3:7)在1wt%质量分数时介质损耗因数达到最小值0.076%，CHBP处理后BN在5wt%质量分数介电常数达到最小值1.11；BN质量分数1wt%时达到局部放电起始电场强度最大值22.435 kV/mm；BN:TiO₂ (1:1)质量分数7wt%时经CHBP处理后击穿电场强度达到峰值88.405 kV/mm。研究表明，TiO₂的引入降低了质损耗因数但提高了介电常数，提高了体积电阻率和表面电阻率，降低了局部放电起始电场强度但提高了击穿电压。CHBP处理可以弥补TiO₂引入后的缺点。

Abstract: In order to study the dielectric properties and insulation properties of BN/TiO₂ filled epoxy resin composite materials, BN/TiO₂ epoxy resin composite materials with different filling amounts and mixing ratios were prepared and tested separately. In the following experiments, the dielectric loss factor, the dielectric constant, the volume resistivity, the surface resistivity, the partial discharge initiation electric field strength and breakdown strength for dielectrics were examined or measured. The effect of hyperbranched CHBP treatment on the dielectric properties and insulation properties of composites was studied. The study found that the dielectric loss factor of BN:TiO₂ (3:7) after CHBP treatment reached the minimum value of 0.076% at 1wt% mass fraction, and the dielectric constant of BN reached the minimum value of 1.11 at 5wt% mass fraction after CHBP Hyperbranched Polyester; BN mass fraction was 1wt% when the initial electric field intensity of partial discharge reaches the maximum value of 22.435 kV/mm; when the mass fraction of BN:TiO₂ (1:1) is 7wt%, the breakdown strength for dielectrics reached the peak value of 88.405 kV/mm after CHBP Hyperbranched Polyester. The results indicate that, the introduction of TiO₂ reduces the mass loss factor but increases the dielectric constant, increases the volume resistivity and surface resistivity, reduces the initial electric field intensity of partial discharge but increases the breakdown voltage. CHBP Hyperbranched Polyester can make up for the shortcomings of the introduction of TiO₂.