High-performance epoxy (EP) composites with excellent thermal conductivity and dielectric properties have attracted increasing attention for effective thermal management. In this work, three-dimensional (3D) structural functional fillers were prepared by an electrostatic self-assembly approach. The negatively charged carbon nanotubes (nCNTs) prepared by carboxylation on the surface of CNTs were attached to the positively charged boron nitride (pBN) to form the 3D pBN@nCNTs functional fillers. The morphological characterizations of the formed 3D pBN@nCNTs fillers and epoxy composites were established, illustrating that nCNTs were linearly overlapped between the BN sheets, thus forming a 3D heat conduction network in the epoxy matrix. The synergistic effect of pBN with nCNTs on the enhancement of thermal conductivity and dielectric properties of composites was systematically studied. The experimental results demonstrated that the thermal conductivity of pBN@nCNTs/EP composites could reach 1.986 W m⁻¹K⁻¹ with the loading of 50 wt% fillers at 10:1 mass ratio of pBN:nCNTs, which is 464% and 124% higher than that of pure EP and BN/EP, respectively. Simultaneously, the dielectric permittivity was successfully increased to 15.14. Moreover, the thermal stability of the composites was synchronously enhanced. This study provides a facile path to fabricate thermosetting polymer composites with high thermal conductivity and dielectric properties.

具有出色的导热性和介电性能的高性能环氧（EP）复合材料已受到越来越多的关注，以进行有效的热管理。在这项工作中，通过静电自组装方法制备了三维（3D）结构功能填料。将通过羧基化在CNT表面上制备的带负电荷的碳纳米管（nCNT）连接到带正电荷的氮化硼（pBN）上，以形成3D pBN @ nCNTs功能性填料。建立了所形成的3D pBN @ nCNTs填料和环氧复合材料的形貌特征，表明nCNT在BN片之间线性重叠，从而在环氧基质中形成3D导热网络。系统地研究了pBN与nCNT的协同作用，以增强复合材料的导热性和介电性能。实验结果表明，pBN @ nCNTs / EP复合材料的热导率可达到1.986 W m^-1 K ^-1，在pBN：nCNT的质量比为10：1的情况下填充50 wt％的填料，分别比纯EP和BN / EP高464％和124％。同时，介电常数成功提高到15.14。此外，复合材料的热稳定性同步增强。这项研究为制造具有高导热率和介电性能的热固性聚合物复合材料提供了一条简便的途径。