Ultra-strength polyurethane/MOF-derived composites with self-healing and recycling capabilities and highly efficient microwave absorption properties.

The development of multifunctional electromagnetic wave (EMW) absorption materials is important for addressing the hazards posed by EMWs. Herein, we designed a polyurethane-based EMW absorption material (P₆H₇-B₃O₃-CoNC@rGo_6%) with high strength, self-healing ability and highly efficient EMW absorption properties. The P₆H₇-B₃O₃-CoNC@rGo_6% shows excellent EMW absorption performance with a minimum reflection loss (RL_min) of −47.1 dB at 12.8 GHz, an effective absorption bandwidth (EAB) of 4.11 GHz at 2 mm thickness and a very low filler mass loading of only 6 wt%. The polyurethane (P₆H₇-B₃O₃) and the nanocomposites (P₆H₇-B₃O₃-CoNC@rGo_6%) exhibit excellent mechanical properties with tensile strength of 62.79 MPa and 22.04 MPa, respectively. Additionally, the P₆H₇-B₃O₃-CoNC@rGo_6% can rapidly restore to its original state at 85 °C by the ester exchange reaction of boron ester bonds. This strategy provides a new idea for designing polyurethane-based EMW absorption materials and extending the service life of EMW absorption materials. [ABSTRACT FROM AUTHOR]