ZnO纳米颗粒锚定的亚微米碳纤维的制备及其吸波性能

使用静电纺丝技术结合水热法制备了表面锚定ZnO纳米颗粒的亚微米碳纤维（ZnO/SDCFs）复合物，并详细研究了反应溶液的pH值对复合物的结构、组成、电磁特性和吸波性能的影响。结果显示，随着pH值的升高，ZnO的含量增加，介电常数、介电损耗以及电磁衰减能力均下降，但阻抗匹配程度提高。相比于纯碳纤维，所有ZnO/SDCFs复合物的吸波性能均得到不同程度的加强。其中，pH值等于8时所制备的ZnO/SDCFs-8复合物拥有最好的吸波性能，主要归因于电磁衰减能力和阻抗匹配间的更好平衡。当ZnO/SDCFs-8的填充量仅为2.5%（质量分数）、厚度为1.7 mm时，相应吸波涂层的最小反射损耗达到-44.1 dB，低于-10 dB的有效吸收带宽为6.1 GHz，频率范围为11.9~18 GHz；当厚度为3.0 mm时，有效吸收带宽可提高到11.8 GHz（6.2~18 GHz）。

Preparation and Microwave Absorption Properties of ZnO Nanoparticles Anchored on Submicron-Diameter Carbon Fibers

ZnO nanoparticles anchored submicron-diameter carbon fibers (denoted as ZnO/SDCFs) composites were synthesized by electrospinning combined with hydrothermal method. The influences of pH value of the reaction solution on the structure, composition, electromagnetic (EM) characteristics and microwave absorption properties of the products are investigated in details. The results show that with increasing pH value of the solution, the complex permittivity, dielectric loss and EM attenuation ability of as-obtained ZnO/SDCFs composites decrease monotonously due to the increase of ZnO content in composites, in contrast, the EM impedance matching is improved gradually. Compared as the pure SDCFs, the microwave absorption capacities of ZnO/SDCFs composites are enhanced at different degrees. Among all the samples, the ZnO/SDCFs-8 composite prepared in solution with a pH value of 8 owns the best overall absorption properties, which is mainly attributed to the better balance between its EM attenuation capability and impedance matching. For the paraffin composites with only 2.5% (mass fraction) ZnO/SDCFs-8 as absorbent, the minimum reflection loss (RL) reached -44.1 dB at 17.7 GHz, and the effective absorption bandwidth with RL values less than -10 dB was as wide as 6.1 GHz ranging from 11.9 to 18 GHz at a relatively thin matching thickness of 1.7 mm. Moreover, the effective absorption bandwidth can be further increased to 11.8 GHz (6.2~18 GHz) when the absorber thickness was 3.0 mm.