Rigid polymethacrylimide composites foam for efficient electromagnetic dissipation and infrared stealth

With the rapid development of 5G technology, the types and numbers of 5G base stations are becoming increasingly large. The precision electronic devices in base stations are at risk of electromagnetic interference and infrared detection. Therefore, it is of great significance to design lightweight and high-strength protective materials with electromagnetic dissipation and infrared stealth performance. In this paper, a rigid polymethacrylimide (PMI) composite foam is fabricated by in-situ copolymerization and free-foaming process. Stable polymerization of PMI and uniform dispersion of CNT are steady controlled. The appropriate pore size and density effectively enhance mechanical properties of PMI/CNT composite foam (PCF). More importantly, the hierarchical impedance matching can be constructed by systematically assembling PCF and silver coating (Ag), endowing it with a low-reflection electromagnetic dissipation performance. Thickness of the composite material can be effectively reduced. In addition, thermal insulation of PCF and low infrared-emissivity of Ag coating bring an excellent infrared stealth performance for PCF/Ag. Such excellent comprehensive performance makes it desirable to be applied as protection material for 5G base stations.