To address the issue of weak absorption intensity and narrow frequency band in pure dielectric electromagnetic wave (EMW) absorbing materials, this study adopts a simple method to successfully prepare a pure dielectric EMW absorption material by modifying acrylonitrile–methylmethacrylate copolymer carbon microspheres (co-AN-MMA@CS) with capsaicin-like 3,5-dimethylphenol derivative (DMPD). The introduction of DMPD into the carbon microspheres increases the heteroatoms (N, O) in the carbon material, thus resulting in functional groups (-C-N, –NO, and C–O) that enable energy loss through dipole polarization. Additionally, the special morphology of carbon microspheres attached or embedded in carbon sheets derived from DMPD increases the inhomogeneous interfaces, thereby increasing the interface polarization relaxation and further attenuating EMWs. The resulting carbon material with the optimal structure (denoted as CNO-2) exhibits superior EMW absorption properties. At a thickness of 2.50 mm, the minimum reflection loss (RL) reaches −63.10 dB at 13.14 GHz, whereas the maximum effective absorption bandwidth (EAB) reaches 6.81 GHz (8.95–15.76 GHz). CNO-2 has excellent EMW absorption capabilities due to the controllable complex dielectric constant and multiple attenuation mechanisms, including interfacial polarization, dipole polarization, and conduction loss. The CNO absorbers prepared in this study can be used as efficient microwave absorbers for electromagnetic protection applications.

中文翻译：

---

碳微球/碳片作为高效电磁波吸收剂

针对纯介电电磁波（EMW）吸波材料吸收强度弱、频带窄的问题，本研究采用简单的方法，通过改性丙烯腈-甲基丙烯酸甲酯共​​聚物碳微球（co-AN）成功制备了纯介电电磁波吸收材料。 -MMA@CS) 与辣椒素样 3,5-二甲基苯酚衍生物 (DMPD)。将 DMPD 引入碳微球中会增加碳材料中的杂原子（N、O），从而产生官能团（-CN、-NO 和 C-O），从而通过偶极极化实现能量损失。此外，附着或嵌入源自 DMPD 的碳片中的碳微球的特殊形态增加了不均匀界面，从而增加了界面极化弛豫并进一步减弱了 EMW。所得具有最佳结构的碳材料（表示为CNO-2）表现出优异的电磁波吸收性能。在厚度为 2.50 mm 时，最小反射损耗 (RL) 在 13.14 GHz 处达到 -63.10 dB，而最大有效吸收带宽 (EAB) 达到 6.81 GHz (8.95–15.76 GHz)。由于可控的复杂介电常数和多种衰减机制，包括界面极化、偶极极化和传导损耗，CNO-2具有优异的电磁波吸收能力。本研究制备的 CNO 吸收体可用作电磁防护应用的高效微波吸收体。