层间键增强NR/Bi_(2)WO_(6)复合材料γ射线屏蔽及力学性能

γ-ray shielding and mechanical properties of NR/Bi_(2)WO_(6)composites enhanced by interlayer bonds

橡胶基纳米复合材料因其在可穿戴辐射防护设备中的广泛应用,已在核工业领域成为研究焦点。在此研究中,采用水热法合成了Bi_(2)WO_(6)纳米粒子,并通过球磨法制备了WO_(3)和Bi_(2)O_(3)粒子。随后,将这些粒子以质量分数30%分别填充到天然橡胶(Nature Rubber,NR)中,制备了NR/Bi_(2)WO_(6)、NR/WO_(3)和NR/Bi_(2)O_(3)这三种复合材料。研究结果表明:NR/Bi_(2)WO_(6)复合材料对于59.5 keV(^(241)Am)γ射线的屏蔽效果达到了13.6%,这个数值显著高于NR/WO_(3)的7.4%以及NR/Bi_(2)O_(3)的9.2%。研究还发现,相比WO_(3)和Bi_(2)O_(3),Bi_(2)WO_(6)晶体结构中Bi_(2)O_(22)^(+)层与WO_(4)^(2-)层的交错排列形成的层间效应能有效提升γ光子与核外电子碰撞的概率,从而显著提高了复合材料的γ射线防护性能。

[Background]Rubber-based nanocomposites have become a research focus in the nuclear industry due to their wide application in wearable radiation protection devices.[Purpose]This study aims to explore theγ-ray shielding mechanism of composite material of Bi_(2)WO_(6)nanoparticles and natural rubber(NR),so as to provide theoretical support for the further materials preparation of low toxicity,light weight and high efficiency radiation shielding.[Methods]Bismuth tungstate(Bi_(2)WO_(6))nanoparticles synthesized via hydrothermal process,additionally,WO_(3)and Bi_(2)O_(3)particles were prepared by ball milling method.Then,these particles were filled into natural rubber(NR)at the mass fraction of 30%to fabricate three composites:NR/Bi_(2)WO_(6),NR/WO_(3)and NR/Bi_(2)O_(3).Finally,laser particle size analyzer,X-ray diffraction analysis(XRD)and field emission scanning electron microscope(FE-SEM),etc.,were employed to access the mechanical properties of NR/Bi_(2)WO_(6),and theγ-ray shielding effect was evaluated on the basis of theγ-ray shielding effects of Bi_(2)WO_(6),WO_(3)and Bi_(2)O_(3).[Results]The results show that the NR/Bi_(2)WO_(6)nanocomposites achieves aγ-ray shielding factor of 13.6%for 59.5 keV(241Am point source),which is significantly higher than NR/WO_(3)(7.4%)and NR/Bi_(2)O_(3)(9.2%).Furthermore,a comparison of WO_(3)and Bi_(2)O_(3)indicates that the interlayer effect of the Bi_(2)O_(22)^(+)and WO_(4)^(2−)layers in the Bi_(2)WO_(6)cell is conducive to increasing the probability of collisions betweenγphotons and extranuclear electrons.[Conclusions]Theγ-ray shielding performance of NR/Bi_(2)WO_(6)composites is significantly improved by the boundary complementary effect of both K and L layer absorption edges of W and Bi elements existed in Bi_(2)WO_(6)nanoparticles,which enhances the attenuation efficiency of NR/Bi_(2)WO_(6)to theγ-ray.