A lightweight polyurethane-carbon microsphere composite foam for electromagnetic shielding

Abstract

Abstract In this study, we have produced a lightweight foam composite material by a simple freeze-drying method, which is composed of carboxylated multi-walled carbon nanotubes (MWCNTs), mesoporous carbon hollow microspheres (MCHMs), water-based polyurethane (WPU), and polyvinyl alcohol (PVA). MCHMs were prepared by a novel and facile method. We found that the electromagnetic shielding performance of foam composites can be adjusted by adjusting the density of foam composites, and the electromagnetic shielding performance of composites can be enhanced through the synergistic effect of hollow mesoporous carbon and MWCNTs. The composite material with a density of 232.8042 mg·cm−3 and 40 wt% MWCNT has a δ of 30.2 S·m−1 and SE of 23 dB. After adding 10 wt% MCHMs to the composite material, δ reaches 33.2 S·m−1, and SE reaches 28 dB. Both absorption losses accounted for 70%. The increase in the content of MWCNT, the increase in density, and the introduction of MCHMs all have a positive effect on the δ and SE of the composite material.