Abstract：
The development of cellulose derived carbon-based composite aerogels with light weight, broad bandwidth and strong absorption remains a challenging task. In this work, the cellulose derived carbon/reduced graphene oxide composite aerogels were prepared by a two-stage process of chemical crosslinking and high-temperature carbonization. The results revealed that the as-fabricated binary composite aerogels had a unique lightweight characteristic and three-dimensional porous network structure, which was chemically crosslinked by epichlorohydrin. Furthermore, the weight concentration of graphene oxide (GO) had a notable influence on the electromagnetic parameters and microwave absorption properties of the composite aerogels. The obtained binary composite aerogel possessed the optimal microwave dissipation capability when the concentration of GO was 1.5 mg/mL. Remarkably, the minimum reflection loss reached -50.42 dB at a thickness of 2.47 mm and a filling ratio of 17.5 wt%. Concurrently, the composite aerogel with a comparable thickness of 2.73 mm showed a wide effective absorption bandwidth of 7.28 GHz, spanning the total Ku-band and extending into a portion of the X-band. The radar cross section contribution of binary composite aerogels in the far-field was also simulated by computer simulation technique. In addition, the potential microwave attenuation mechanism was proposed. It was believed that the results of this paper would offer a reference for the preparation of cellulose derived carbon-based composite aerogels as efficient and broadband microwave absorbers.
摘要：
轻质纤维素衍生碳基复合气凝胶的研制,宽的带宽和强吸收仍然是一个具有挑战性的任务。在这项工作中,通过化学交联和高温碳化两阶段工艺制备了纤维素衍生的碳/还原氧化石墨烯复合气凝胶。结果表明，所制备的二元复合气凝胶具有独特的轻质特性和三维多孔网络结构，由表氯醇化学交联。此外，氧化石墨烯(GO)的质量浓度对复合气凝胶的电磁参数和微波吸收性能有显著影响。当GO浓度为1.5mg/mL时，所得二元复合气凝胶具有最佳的微波耗散能力。值得注意的是,在厚度为2.47mm和填充率为17.5wt％的情况下，最小反射损耗达到-50.42dB。同时,厚度为2.73mm的复合气凝胶显示出7.28GHz的宽有效吸收带宽，跨越整个Ku波段并延伸到X波段的一部分。还通过计算机模拟技术模拟了二元复合气凝胶在远场中的雷达横截面贡献。此外,提出了潜在的微波衰减机理。相信本文的研究结果将为制备纤维素衍生碳基复合气凝胶作为高效宽带微波吸收剂提供参考。
