Melamine foam-supported 3D interconnected boron nitride nanosheets network encapsulated in epoxy to achieve significant thermal conductivity enhancement at an ultralow filler loading

Realizing high-efficiency thermal conductivity enhancement at low filler loading has a great significance for thermally conductive composite. Herein, three-dimensional (3D) boron nitride nanosheets (BNNSs) wrapped melamine foams (MF@BNNS) were first fabricated by repeated layer-by-layer (L-B-L) assembly using melamine skeleton as substrate and BNNSs as building blocks. The resultant MF@BNNS scaffold with order and interconnected BNNS layer, as a thermally conductive network, was further infiltrated with epoxy resin. As a consequence, a relatively high thermal conductivity of 0.6 W m−1 K−1 was achieved at an ultralow BNNS loading of ∼1.1 vol%, which is equivalent to a thermal conductivity enhancement of 233% compared to epoxy resin. Besides, the obtained epoxy composite also possesses a good mechanical property and excellent electrical insulativity. This method can be further extended to construct 3D filler network of other 2D layered materials on the melamine foam for high-performance composite

在低填料含量下实现高效热导率增强对导热复合材料具有重要意义。在此，以三聚氰胺骨架为基底，氮化硼纳米片（BNNSs）为构建单元，通过反复逐层组装首次制备了三维（3D）氮化硼纳米片包裹的三聚氰胺泡沫（MF@BNNS）。所得的具有有序且相互连接的BNNS层的MF@BNNS支架作为导热网络，进一步用环氧树脂浸渍。结果，在约1.1 vol%的超低BNNS含量下，实现了0.6 W m⁻¹K⁻¹的较高热导率，与环氧树脂相比，热导率提高了233%。此外，所得的环氧复合材料还具有良好的力学性能和优异的电绝缘性。该方法可进一步扩展到在三聚氰胺泡沫上构建其他二维层状材料的三维填料网络，以用于高性能复合材料。