One-step preparation of sea urchin-like conducting polypyrrole-modified porous carbonyl iron powders with excellent microwave absorption properties

Carbonyl iron powder (CIP) is a common microwave absorber frequently utilized to prepare microwave-absorbing materials. However, it exhibits only magnetic loss and no dielectric loss, which inevitably affects its wave-absorbing performance. Here, porous carbonyl iron powder (p-CIP) modified with conductive polypyrrole (PPy) was successfully prepared by one-step chemical etching and in-situ polymerization and then utilized to fabricate epoxy composites with high microwave absorption intensity. The scanning electron microscopy images revealed that conductive PPy was encapsulated on the surface of p-CIP. The reflection loss of the P-200 sample is -41.2dB at 2.2mm thickness. Reduction of the sample thickness to 1.8 mm resulted in a still acceptable reflection loss of -35.5 dB. Moreover, the effective absorption bandwidth widened to approximately 6.75 GHz (10.55–17.3 GHz). This provides a valuable approach for the development of microwave-absorbing materials with high absorption capacity.