Anisotropic electromagnetic wave absorption performance of Polyimide/multi-walled carbon nanotubes composite aerogels with aligned slit-like channels structure

• Published in: Composites. Part A, Applied science and manufacturing Vol. 154; p. 106781
• Main Authors: Ni, Long, Chen, Shaokang, Jiang, Xinyue, Luo, Yinfu, Zou, Huawei, Liu, Pengbo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2022
• Subjects: A. Multi-walled carbon nanotubes; A. Polyimide composite aerogel; B. Anisotropic performances; B. Electromagnetic wave absorption; B. Electromagnetic wave absorption; A. Multi-walled carbon nanotubes; B. Anisotropic performances; A. Polyimide composite aerogel
• ISSN: 1359-835X; 1878-5840
• DOI: 10.1016/j.compositesa.2021.106781

[Display omitted] •The PI/MWCNTs-COOH composite aerogels had highly aligned slit-like channels structures.•The electromagnetic wave absorption performance can be modulated by chemical components and anisotropic pore structure.•The direction perpendicular to the aligned slit-like channels presented more significant electromagnetic wave absorption performances.•Dielectric loss and impedance matching were the main contributors to the enhanced electromagnetic wave absorption. Polyimide/carboxyl functionalized multi-walled carbon nanotubes (PI/MWCNTs-COOH) composite aerogels with aligned slit-like channels structure were synthesized through unidirectional freezing, freeze-drying and thermal imidization process in sequence. The composite aerogels with high porosity and low density exhibited highly aligned slit-like channels structure, which further imparted anisotropic electrical conductivity, electromagnetic wave absorption, and compression properties to the aerogels. PI/MWCNTs-COOH-16phr composite aerogel showed the minimum reflection loss (RLmin) of −52 dB at 12.8 GHz and effective absorption bandwidth of 6.7 GHz (10.6 ∼ 17.3 GHz) with a thickness of only 2.5 mm in the perpendicular direction to the aligned slit-like channels, while its RLmin was only −11 dB at 15.9 GHz in the orientation direction of slit-like channels. The composite aerogel had prominent thermal stability, with T5% in nitrogen up to 564 °C. The high temperature resistant and lightweight polyimide-based highly efficient EMW absorbing structural material manufactured by this research had great potential for aerospace applications.