Zhang Danfeng, Hao Zhifeng, Qian Yannan, Huang Yinxin, Yang Zhenda, Qibai Wu
Guangdong University of Technology, Guangzhou, 510006, China.
Foshan University, Foshan, 528000, China.
Sci Rep. 2017 Mar 28;7(1):479. doi: 10.1038/s41598-017-00372-9.
Heat-treatments may change the defect and surface organic groups of carbon nanotubes (CNTs), and lead to significant changes in the microwave electromagnetic parameter of CNTs. In this paper, the effect of heat-treatment time and temperature on the complex dielectric constant and permeability as well as the microwave reflectivity of CNTs was investigated. The experimental results indicated that the microwave absorption property of CNTs arises mainly from the high permittivity and consequent dielectric loss. Moreover, the heat-treatment resulted in increased dielectric constant of CNTs and significant improvement of the microwave absorption at frequency values of 2-18 GHz. The microwave reflectivity of CNT composites with a coating thickness of 3 mm was simulated by using the electromagnetic parameters. The absorption peak of CNTs treated at 700 °C had an amplitude of R = -48 dB, which occurred at 9 GHz. Below -10 dB, the composites treated at 900 °C had a bandwidth of 7 GHz. The position of the absorption peak concurred with the measured results. The results indicated that the microwave-absorption properties can be modified by adjusting heat-treatment temperature and time.
热处理可能会改变碳纳米管（CNT）的缺陷和表面有机基团，并导致CNT的微波电磁参数发生显著变化。本文研究了热处理时间和温度对CNT复介电常数、磁导率以及微波反射率的影响。实验结果表明，CNT的微波吸收特性主要源于高介电常数以及由此产生的介电损耗。此外，热处理导致CNT的介电常数增加，并且在2 - 18 GHz频率范围内微波吸收有显著改善。利用电磁参数模拟了涂层厚度为3 mm的CNT复合材料的微波反射率。在700 °C处理的CNT的吸收峰幅度为R = -48 dB，出现在9 GHz处。在-10 dB以下，在900 °C处理的复合材料带宽为7 GHz。吸收峰的位置与测量结果一致。结果表明，可以通过调整热处理温度和时间来改变微波吸收特性。
