“Brick‐Mortar” Segregated Structure Enables Fluororubber Composites With Simultaneous High Electromagnetic Interference Shielding and Mechanical Robustness

ABSTRACT Fluororubber (fluorine kautschuk material [FKM]) composites exhibiting outstanding electromagnetic interference (EMI) shielding capability are crucial and irreplaceable sealing materials used in the aerospace industry. However, the tradeoff between its superb shielding effectiveness (SE) and exceptional mechanical properties presents a considerable challenge. Here, FKM‐based EMI shielding composites featuring high SE and mechanical properties were fabricated via an innovative strategy involving construction of “brick‐mortar” segregated structure. In the prepared FKM composites, an FKM/carbon nanotube matrix serves as “mortar” phase that forms an interconnected conductive passage, whereas an FKM/conductive carbon black matrix functions as the “brick” phase. This unique structure endows the prepared FKM composites with a stress of 8.0 MPa and an electrical conductivity of 55.8 S/m, resulting in an SE of 43.0 dB. Importantly, after 1500 friction cycles or immersion in harsh solutions for 24 h, the SE values of the composites are 95% or 100% of the initial values, respectively, implying excellent wear and solvent resistances. Furthermore, the prepared FKM composites exhibit a satisfying thermal conductivity of 0.318 W/m K. Owing to these excellent characteristics, the FKM‐based shielding materials fulfill the application requirements in field of all weather‐sealing devices.