Microwave absorption properties of multi-walled carbon nanotube (outer diameter 20–30 nm)–epoxy composites from 1 to 26.5 GHz

•High absorption ratio up to 60–65% was achieved for MWCNT–epoxy composite.•Low reflection and transmission were recorded in CNT–epoxy composites.•MWCNT–epoxy composites show a potential microwave technology application.•MA strongly depends on the loadings of MWCNTs in epoxy composites.

In this work, multi-walled carbon nanotube (MWCNT) (outer diameters (OD) in the range of 20–30 nm)–epoxy composites were fabricated. The MWCNT loadings in the polymer composites were controlled from 1–10 wt.%. An Agilent PNA Network analyzer was utilized in the measurements of microwave absorption (MA) properties of these MWCNT–epoxy composites over a wide frequency range of 1–26.5 GHz. The measurement results showed that MA strongly depends on MWCNT loadings in the composites. In addition, the microwave reflection, transmission, and dielectric permittivity of the MWCNT–epoxy composites are also investigated. The composite with 8 wt.% MWCNT loading shows high microwave absorption as well as low reflection and transmission. These MWCNT–epoxy composites with 8–10 wt.% MWCNT loadings show a significant potential for microwave technology applications.

Graphical abstractAbsorption ratio vs frequency graph showing high microwave absorption.Figure optionsDownload full-size imageDownload as PowerPoint slide