KGM Derived CNTs Foam/Epoxy Composites with Excellent Microwave Absorbing Performance

We adopted a green, economical and simple method in which konjac glucomannan (KGM) was used as a carrier to support CNTs to construct a three-dimensional structure filled with epoxy resin to improve the absorbing performance of epoxy resin. Through the reflection of the internal multi-level pore structure and the dielectric loss effect of CNTs, the dissipation and absorption of electromagnetic waves are realized. This KGM derived CNTs foam exhibits high specific microwave absorption performance with a minimum absorption of −25.2 dB at 11.3 GHz and a qualified bandwidth of around 2.89 GHz (RL⩽ −10 dB), which is achieved by KDCF5/Epoxy with the coating layer thickness of 1.8 mm. We provide a novel and cost-effective method to achieve excellent absorbing performance under thin thickness and low load. The CNTs foam also has a lower density (6.5 mg/cm³) and can improve the absorbing properties of the epoxy while maintaining its various advantages, thereby expanding the application range of the epoxy resin.