Lightweight and thermal insulation fabric-based composite foam for high-performance electromagnetic interference shielding

With the rapid development of electronic devices, electromagnetic interference (EMI) has posed serious threats to human health. Therefore, wearable materials with high EMI shielding performance are urgently required for protecting people from electromagnetic radiation. Herein, electroless plating and compression molding methods were utilized to fabricate sandwich structured composite foam. Aramid-carbon blend fabrics with Co–Ni coatings were selected as the surfaces, and the porous polyurethane (PU) foam doped with diverse content of carbon nanotubes (CNTs) served as the core lightweight layer. With the CNTs doping content of 3 wt%, a 3D conductive network is precisely constructed in the core foam with a tested 13.82 GPa tensile strength. Through a “reflection-absorption-reflection” triple-loss mechanism, the resulting composite foam possesses a favorable average EMI shielding effectiveness (SE) of 73.9 dB in the X band (8–12 GHz), which was far more than the requirement of 30 dB for common commercial EMI SE. In addition, the porous structure exhibits excellent thermal insulation properties within a wide range of temperature (0–150 °C) while presenting a low thermal conductivity of 0.0695 W/(m·K). Finally, the prepared composites were applied to the simulation scene of electromagnetic protection to explore its reliability and practicability as a wearable electromagnetic wave proof material. With the good combination of mechanical properties, thermal properties and excellent electromagnetic shielding properties, the prepared composites have a great application prospect in electromagnetic protective materials.