Floral-structured bimetallic Co/Ni@CuBTC for enhancing the EMW absorption and fire safety of epoxy: an integrated solution for radar stealth, fire retardant and thermal management

Abstract

For the application of intelligent equipment in fire rescue and anti-terrorism, the urgent need of shell materials with comprehensive performance, including radar wave absorption and fire safety, is raised. This study presents the epoxy resin (EP) composite incorporating a floral-structured bimetallic Co/Ni@CuBTC (ACM) with enhanced EMW absorption, flame retardancy and thermal management. The results show that the absorption rate of ACM at 3 mm thickness reaches -42.25 dB for 11.5 GHz EMW, and the dissipation to radar waves at -180^o to 180^o in radar cross section (RCS) simulation reaches -40.2 dB. The EP composite with 5 wt% ACM can block cell phone (800 MHz) and Bluetooth signals (2.4 GHz) at 3 mm thickness. The EP composite with 3 wt% ACM-3 (EP/ACM 3 %) presented the lowest peak heat release rate of 811.2 kW·m^-2, which decreased by 39.5 % compared with pure EP, meanwhile it reached the V-1 rate in UL-94 test, showing a significant improvement in flame retardancy. The thermal conductivity (λ) of EP/ACM 3 % reached 0.811 Wm^-1K^-1, which is 21.9 % higher than that of pure EP, reducing the risk of heat accumulation. The EP/ACM composite, with its integrated capabilities in EMW absorption, flame retardant and thermal management, holds promising applications in unmanned fire rescue and anti-terrorism in future.