Xiao Zhong, Mukun He, Chenyang Zhang, Yongqiang Guo*, Jinwen Hu and Junwei Gu*. Heterostructured BN@Co-C@C Endowing Polyester Composites Excellent Thermal Conductivity and Microwave Absorption at C Band. Advanced Functional Materials, 2024, 10.1002/adfm.202313544. 2022IF=19.0.（1区材料科学Top期刊）https://doi.org/10.1002/adfm.202313544

Abstract

The trends of miniaturization, lightweight, and high integration in electronics have brought serious issues in heat dissipation and electromagnetic compatibility, and also limited the simultaneous use of thermally conductive & microwave absorption materials. Therefore, it is imperative to design materials that possess those dual functions. In this work, one-pot method is used to anchor zeolitic imidazolate framework ZIF-67 coated with polydopamine (PDA) on boron nitride (BN) to obtain BN@ZIF-67@PDA. The pyrolysis product BN@Co-C@C is used as heterostructured thermally conductive/microwave absorption fillers and blended with polyethylene terephthalate (PET) to prepare BN@Co-C@C/PET composites. When the mass ratio of BN to ZIF-67@PDA is 7.5:1 and the mass fraction of BN7.5@Co-C@C is 45 wt%, the BN7.5@Co-C@C/PET composites exhibit excellent thermal conductivities and microwave absorption performances. The thermal conductivity coefficient is 5.37 W m-1 K-1, which is 35.8 times higher than that of PET (0.15 W m-1 K-1), and also higher than that of 45 wt% (BN7.5/Co-C@C)/PET composites (4.03 W m-1 K-1) prepared by directly mixing. The minimum reflection loss of 45 wt% BN7.5@Co-C@C/PET composites is -63.1 dB at 4.72 GHz, and corresponding effective absorption bandwidth is 1.28 GHz (4.08~5.36 GHz), achieving excellent microwave absorption performance at C band.电子产品的小型化、轻薄化和高度集成化等发展趋势带来了愈发严重的散热和电磁兼容问题，而其狭窄的内部空间难以支持导热材料和吸波材料的叠加使用，设计制备兼具导热/吸波双功能材料势在必行。本文采用一锅法并结合“正向沉积-逆向生长”机制将聚多巴胺（PDA）包覆的沸石咪唑酯骨架ZIF-67分散锚定于BN（BN@ZIF-67@PDA）表面，并将其热解产物BN@Co-C@C作为异质结构导热/吸波功能填料与聚对苯二甲酸乙二醇酯（PET）共混制备BN@Co-C@C/PET复合材料。当BN与ZIF-67@PDA的质量比为7.5:1且BN7.5@Co-C@C的质量分数为45 wt%时，BN7.5@Co-C@C/PET复合材料兼具出色的导热和吸波性能，其导热系数（λ）达到5.37 W/(m·K)，是纯PET（0.15 W/(m·K)）的35.8倍，也远优于相同质量分数下直接混合的(BN7.5/Co-C@C)/PET复合材料（4.03 W/(m·K)）。采用同轴法测试并计算得出在频率为4.72 GHz时，45 wt% BN7.5@Co-C@C/PET复合材料的最小反射损耗（RLmin）达-63.1 dB、对应有效吸收带宽（EAB）为1.28 GHz（4.08~5.36 GHz），实现了C波段优异的电磁波吸收性能。

论文亮点

1. 利用PDA的超强黏附性并结合“正向沉积-逆向生长”机制，通过一锅法将ZIF-67分散锚定在BN表面，将其热解产物BN@Co-C@C作为异质结构导热/吸波填料与PET共混制备了BN@Co-C@C/PET复合材料。

2. 当BN与ZIF-67@PDA的质量比为7.5:1且BN7.5@Co-C@C的质量分数为45 wt%时，BN7.5@Co-C@C/PET复合材料λ达到5.37 W/(m·K)，是纯PET（0.15 W/(m·K)）的35.8倍，也远优于相同质量分数下直接混合的(BN7.5/Co-C@C)/PET复合材料（4.03 W/(m·K)）。

3. 测试频率为4.72 GHz时，45 wt% BN7.5@Co-C@C/PET复合材料的RLmin达-63.1 dB、对应EAB为1.28 GHz（4.08~5.36 GHz），实现了C波段优异的电磁波吸收性能。

第一作者：钟洨

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