关键词: 核壳结构, 复合材料, 磁性材料, 紫外光吸收, 电磁波吸收

Abstract: With the further advancement of the electronic information era, the wide application of various types of electronic equipment has brought convenience but also produced a large number of electromagnetic waves. These electromagnetic waves not only threaten the stealth performance of military equipment but also may be harmful to human health. Wave-absorbing materials can convert incident electromagnetic waves into other forms of energy and loss, reduce electromagnetic wave reflection and scattering, and further reduce electromagnetic interference and pollution. Therefore, investigating electromagnetic wave-absorbing materials is not only an urgent necessity but also holds profound scientific and practical importance. In the field of wave-absorbing engineering, wave-absorbing agents as the core component are the key unit to realize the wave-absorbing function, and their performance directly determines the overall performance of wave-absorbing materials. However, the current wave-absorbing agent system still faces numerous pressing challenges. Firstly, the components of wave-absorbing agents are relatively homogeneous, their microstructural design is overly simplistic, and they lack sophisticated multi-level architectures. This homogeneity seriously limits their further improvement in key performance indicators such as broadband absorption, high-intensity electromagnetic wave absorption, and lightweight. Secondly, the performance of wave absorbers in extreme or complex environments has significant shortcomings. For example, in a strong ultraviolet light environment, the internal structure of the wave-absorbing material is very susceptible to the strong radiation effect of ultraviolet rays, resulting in molecular chain breakage, crosslinking structure failure and other problems. This structural damage will not only weaken the electromagnetic wave absorption ability of wave-absorbing materials but also further trigger coating peeling and cracking, and ultimately lead to the complete failure of wave-absorbing performance. Aiming at the above-mentioned problems, the present study prepared Fe₃O₄@TiO₂@PANI wave-absorbing agent with core-shell structure by solvothermal and in-situ polymerization, with Fe₃O₄ nanometer as the core and anatase TiO₂ and polyaniline (PANI) as the shell. The study systematically studied its microstructure, magnetic properties, ultraviolet absorbing properties and wave-absorbing properties. The results show that the introduction of TiO₂ endows it with ultraviolet light absorption capacity. Although the introduction of the PANI component reduces the saturation magnetization strength, it also endows the absorber with a magnetic/dielectric double loss mechanism and good impedance matching characteristics. The core-shell structure facilitates interfacial polarization and multiple reflection/scattering effects. The Fe₃O₄@TiO₂@PANI microwave absorbent exhibits remarkably high absorption efficiency and broad absorption range for ultraviolet (UV) light. Within the ultraviolet UV wavelength range of 200–400 nm, the UV absorbance reaches 92.3% and the average UV absorption is above 90%, demonstrating excellent UV protection capability. Fe₃O₄@TiO₂@PANI microwave absorbent also exhibits broadband and high-efficiency electromagnetic wave absorption characteristics. At a thickness of 4.01 mm, the minimum reflection loss value reaches -59.24 dB@7.90 GHz; at a thickness of 2.34 mm, the maximum effective frequency bandwidth of the absorber reaches 5.70 GHz (12.20 GHz–17.90 GHz). This study provides ideas for the design of new high-performance microwave absorbers to cope with extreme complex environments.

Key words: core-shell structures, composite materials, magnetic materials, ultraviolet protective light absorption, electromagnetic wave absorption