关键词: 天然皮革, 纳米稀土粒子, X射线, 可穿戴防护材料, 衰减效率

Abstract:

X-rays are widely used in many fields, including medical imaging, chemical structure analysis, and nondestructive examinations. However, long-term X-ray exposure is harmful to human health. Hence, radiation protection materials, especially wearable materials with outstanding performances, are in need of development. Lead (Pb) plates are commonly used as traditional radiation protection materials but have the disadvantages of heavy mass, toxicity, and poor wearability. Cement and alloy also are used to shield the X-ray, whereas application is limited by its heavy mass. In recent years, the wearable polymer based radiation protection was developed but has the defect which is low interfacial compatibility, resulting in poor shielding properties of the material. The K or L absorption edge of an element plays a major role in the attenuation of X-ray photon energy, and has a significant attenuation effect on X-ray photons with similar energy. As an alternative, it has been reported that the K absorption edge of rare earth (RE) elements is located in the range of 40–80 keV, which corresponds to the energy range of X-rays and medical X-ray energy range. Additionally, natural leather (NL) is an abundant natural biomass that is composed of multi-layered collagen fibers and contains amino (―NH₂), carboxyl (―COOH), and hydroxyl (―OH) groups. We believe that RE nanoparticles can be uniformly immobilized and stabilized by NL. In this study, we developed a novel strategy to prepare X-ray radiation protective materials by combining RE nanoparticles with NL. NL-based protective materials have the advantages of being lightweight and wearable while providing excellent protection. NL-based RE oxide nanoparticle composites (RE-NL) were successfully prepared by a "retanning" method and verified by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM). X-ray protection tests showed that La-NL had the best shielding performance compared to the other tested RE oxide-loaded NLs owing to the small difference between the K-edge energy of La and the incident energy. Moreover, La_7.80-NL (La₂O₃ content of 7.80 mmol·cm^-3, 0.7 mm) showed better protection performance than a Pb plate with a high-Z elemental content (54.7 mmol·cm^-3, 0.25 mm) at 40–80 keV, confirming that the uniform distribution of RE oxides in NL provides enhanced X-ray shielding performance. The RE-NL also displayed a much better tensile strength, tear strength, and softness compared with polymer-based RE oxide composites. Meanwhile, it has the foldability and character of tailor. Therefore, the reported NL-based RE protective materials show promising potential for various scenarios requiring radiation protection.

Key words: Nature leather, Rare earth nanoparticle, X-ray, Wearable protective material, Attenuation efficiency