改性BN-Si-B/环氧树脂复合材料的制备及绝缘性能

Preparation and insulating properties of modified BN-Si-B/epoxy resin composites

电晕放电影响电气设备的稳定运行和使用寿命,提高绝缘材料的耐电晕性能对于保证电气设备的正常运行具有重要意义。本文利用硅烷偶联剂改性氮化硼(BN)制备改性BN(fBN),并将其与分散剂(有机硅硼复合氧化物(Si-B))共混对环氧树脂(EP)进行了改性。采用共混法和热固法制备了不同fBN含量的f BN-Si-B/EP复合材料,提高了环氧树脂的耐电晕寿命。实验结果表明:在30℃和30 kV·mm^(-1)电场强度下,f BN-Si-B/EP复合材料的耐电晕寿命最高可达114.8 h,是纯环氧树脂5.01倍。随着fBN掺杂量的增加,fBNSi-B/EP复合材料的介电常数呈现增加的趋势。同时,该复合材料的体积电阻率和击穿场强则表现出先降低后增加的趋势。少量fBN的加入可以降低复合材料的相对介电常数,抑制介电损耗增加。虽然fBN-Si-B/EP复合材料的击穿场强和体积电阻率略微降低,体积电阻率极小值为6.65×10^(14)Ω·cm,击穿场强极小值为24.04 kV·mm^(-1),但仍具有较好的绝缘性能。

Corona discharge can adversely affect the stable operation and service life of electrical equipment.There-fore,it is crucial to enhance the corona resistance of insulation materials to ensure the normal functioning of elec-trical equipment.In this study,modified BN(fBN)was synthesized by treating boron nitride(BN)with a silane coupling agent,and subsequently blended with dispersant(organosilicon boron composite oxide(Si-B)to modify epoxy resin(EP).The fBN-Si-B/EP composites with different fBN contents were prepared by blending and thermosetting methods.The corona resistance life of epoxy resin was significantly enhanced.The experimental findings revealed that the corona resistance life of fBN-Si-B/EP composites at an electric field strength of 30kV·mm^(-1)and temperature of 30℃ was up to 114.8 h,which was 5.01 times greater than that of pure epoxy resin.The dielectric constant of the fBN-Si-B/EP composite shows an increasing trend with the increase of the fBN dop-ing.At the same time,the volume resistivity and breakdown strength of the composites show a trend of decreasing and then increasing.The addition of a small amount of fBN can reduce the relative dielectric constant of the com-posite and suppress the increase of dielectric loss.While the breakdown strength and volume resistivity of fBN-Si-B/EP composites are slightly reduced with the addition of fBN particles,with a minimum volume resistivity of 6.65×10^(14)Ωcm and a minimum breakdown strength of 24.04 kV·mm^(-1),they still exhibit good insulation properties.