BNNSs/液晶环氧纤维复合薄膜的导热性能  

Thermal Conductivity of Nano-boron Nitride Composite Film/Liquid Crystalline Epoxy Fiber

作　　者：杨森元 黄正勇[1] 张樱凡 李剑[1] 尚恺 王浩欢 YANG Senyuan;HUANG Zhengyong;ZHANG Yingfan;LI Jian;SHANG Kai;WANG Haohuan(State Key Laboratory of Power Transmission Equipment&System Security and New Technology,School of Electrical Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400044

出　　处：《高电压技术》2022年第9期3551-3562,共12页High Voltage Engineering

基　　金：国家自然科学基金(51877023;51707016)。

摘　　要：液晶环氧树脂导热性能较差,耐热性不够高,使得电力、电子器件运行过程中散热困难,温度升高导致环氧树脂绝缘发生劣化,大大影响了电力、电子器件的使用可靠性和寿命。该文开发了制备高取向度液晶环氧纤维薄膜的静电纺丝方法和工艺,结合真空抽滤方法向纤维薄膜中填充纳米氮化硼(nano boron nitride,BNNSs),进一步制备了填充取向型纳米氮化硼/液晶环氧纤维复合导热薄膜,研究了液晶环氧纤维直径和BNNSs填充浓度对BNNSs/液晶环氧树脂导热复合薄膜的导热性能和交流击穿强度的影响规律。结果表明:液晶环氧树脂纤维薄膜的面内热导率随着纤维直径的减小而增大,当纤维直径减小至280 nm时,热导率为0.699 W/(m·K);当填充BNNSs导热填料后,BNNSs/液晶环氧树脂导热复合薄膜的面内热导率随填料浓度增大而急剧上升,在填充量为15%时可以达到5.88 W/(m·K),比280 nm直径的纯薄膜提高了779%。同时发现,液晶环氧树脂纤维薄膜在直径较细的情况下交流击穿强度较高,280 nm纤维薄膜的击穿强度为26.55 kV/mm,BNNSs导热填料的添加可以减小薄膜复合材料的热击穿,填充量为10%时工频击穿强度提高最明显,提高了近11%,达到29.47kV/mm。证明了BNNSs既能够明显增强液晶环氧树脂复合薄膜材料的导热性能,又保持了复合材料良好的电气绝缘性能。The poor thermal conductivity and heat resistance of liquid crystalline epoxy resin make it difficult to dissipate heat during the operation of electric and electronic devices, and the rising temperature leads to the deterioration of epoxy resin insulation, which greatly impairs the reliability and life of electric and electronic devices. The electrospinning method and process for preparing high orientation liquid crystalline epoxy fiber thin films were developed in this paper.Nano boron nitride(BNNSs) was filled into the fiber films by vacuum filtration method, and thermal-conductive thin films which were filled with the oriented nano boron nitride/liquid crystalline epoxy fiber composite were further prepared. The effects of liquid crystalline epoxy fiber diameter and nano boron nitride filling concentration on the thermal properties and the AC breakdown strength of BNNSs/liquid crystal epoxy resin composite films were studied. The results show that the in-plane thermal conductivity of liquid crystalline epoxy resin fiber film increases with the decrease of fiber diameter. When the fiber diameter decreases to 280 nm, the thermal conductivity is 0.699 W/(m·K). When the BNNSs thermal conductive filler is filled, the in-plane thermal conductivity of BNNSs/liquid crystalline epoxy resin thermal conductive composite film increases sharply with the increase of filler concentration. When the filler content is 15%, the in-plane thermal conductivity can reach 5.88 W/(m·K), which is 779% higher than that of diameter. At the same time, it is found that the AC breakdown strength of the liquid crystalline epoxy resin fiber film is high when the diameter is small,and the breakdown strength of the 280 nm fiber film is 26.55 kV/mm. The addition of BNNSs thermal conductive filler can reduce the thermal breakdown of the film composite. When the filler content is 10%, the power frequency breakdown strength increases most significantly, which increases by nearly 11%, reaching 29.47 kV/mm. Therefore, it is demonstrated that BNNSs

关 键 词：液晶环氧树脂 氮化硼 纳米纤维素 导热性能 击穿强度 

分 类 号：TB383.2[一般工业技术—材料科学与工程]