Peng Lin, Yinjie Wang, Yuxuan Lan, Ye‐Tang Pan, Jiping Liu
ABSTRACT With the development of technology, modern electronic devices have become increasingly highly integrated, not only generating a large amount of electromagnetic pollution but also posing a risk of fire due to thermal runaway. Meanwhile, traditional protective materials often have single functions, and their preparation processes are complex and difficult to recycle. Therefore, it is of great significance to develop simple and efficient recyclable materials that can simultaneously absorb electromagnetic waves and have both active and passive flame retardancy. By using a one‐step method, a large amount of pale yellow transparent ionic liquid was prepared through the reaction of hexachlorocyclotriphosphazene (HCCP) and 2‐methylimidazole (2‐MIM), and then it was compounded with three types of metal–organic frameworks (MOFs), namely ZIF‐67, UiO‐66, and CALF‐20, to prepare three MOF‐based porous liquids. Through the dip‐coating method, polyurethane foams (PUF) with excellent electromagnetic absorption, flame retardancy, and fire warning capabilities were fabricated, solving the problems of low flame retardancy, insufficient functionality, and weak adhesion of MOF‐based functional coatings. Compared with the reported literature, green and efficient wave‐absorbing materials with flame retardancy and fire warning capabilities were successfully prepared. The entire process was carried out using only ethanol for green preparation and green dual recycling, successfully separating the liquids and MOFs.