Nitrogen-doped eugenol-group polymer carbon microspheres with high-performance microwave (2–18 GHz) absorption

Reasonable heteroatom doping and structural construction can improve the performance of electromagnetic wave (EMW) absorbing materials. Eugenol-acrylate monomer (EAM) with rich double bonds is synthesized from eugenol and acrylic anhydride by esterification without solvation. EAM and acrylonitrile (AN) are used as raw materials, the EAM as a source of carbon, the AN as nitrogen source. According to different molar ratios, a series of eugenol-group polymer microspheres with particle size ranging from 0.8 to 1.5μm are prepared by precipitation polymerization through one-pot method. Furthermore, N-doped carbonization microspheres with excellent EMW absorption properties are prepared by a controlled carbonization process with particle size ranging from 0.4 to 1.0μm. In this study, the molar ratios of EAM and AN are adjusted to optimize the EMW absorption properties of the prepared EMW absorbing materials of carbonization microspheres. It is confirmed that carbonization microspheres have good EMW absorption performance at an EAM to AN ratio of 7:3 and a thickness of 3 mm, the minimum reflection loss (RL min ) is −40.89 dB (12.56 GHz), and the effective absorption bandwidth (EAB) is 5.01 GHz (10.01–15.02 GHz). In this work, derivatives of eugenol with rich double-bond from a wide range of sources are involved in the process of copolymerizing microspheres maintained morphological stability before and after carbonization, which provided an efficient and easy method for the preparation of nitrogen and oxygen doped carbon microspheres, enriched the types of wave absorbing materials, and laid a foundation for future work.