基于元素梯度组合的胶乳基核辐射防护材料宽能谱衰减特性研究

Latex-based radiation shielding material is a kind of polymer / metals (metallic compound) composites with good operability and flexibility，which can attenuate or shield radiation. It is one of the important materials to manufacture the γ radiation shielding products. It is widely used to protect staffs from radiation who work with nuclear materials processing, nuclear medicine and industrial fault diagnosing. The idea of “elements combination” and “gradient design” is a new way to design radiation shielding material. However, the research on this kind of composites is rarely reported till now. The influence of the gradient structure on the radiation attenuation is still mysterious. Besides，the methods by using this idea to prepare novel latex-based radiation protection material remain to be investigated..This research aims to prepare the novel latex-based flexible radiation protection material which can attenuate γ-ray in wide energy spectrum，based on the ideas of “elements combination” and “gradient design”. Here, Gd2O3, WO3 and Bi2O3 will be chosen as the fillers. The gradient shielding layer will be prepared according to the order of decreasing the atomic numbers from the top to the bottom of the layer. On the basis of the above work, the influences of elements combination and gradient structure on the shielding performance will be studied detailed. In the process, the key problems such as how to cover “weak absorption” and how to disperse the fillers will be solved. Ultimately, we hope to obtain the optimal parameters to prepare the latex-based flexible radiation protection materials with better overall performance. This work may be a way to develop novel radiation protection material.

胶乳基核辐射防护材料是一种对放射线具有衰减、屏蔽功能的金属元素/高分子柔性复合材料，是制作抗γ辐射防护制品重要原材料之一。利用元素梯度组合是设计核辐射防护材料的一个新方向，然而，由于该领域研究在国内外刚起步，元素梯度组合对γ射线屏蔽性能的影响及作用机理仍不清楚，还不能对具有较宽能量范围的复杂γ射线实现有效屏蔽。另外，如何将此设计思想应用于胶乳基核辐射防护制品还有待研究。本项目以开发新型胶乳基柔性核辐射防护材料为目标，将多元素组合和梯度设计思想有机地结合，拟选取的功能粒子为Gd2O3、WO3和Bi2O3，屏蔽层宏观上呈现功能粒子原子序数由上自下逐渐减小的梯度结构。在此基础上，探索元素梯度组合对γ射线衰减行为的作用机理，提出解决辐射屏蔽材料“弱吸收区”和金属及其化合物功能粒子与胶乳相容性等关键问题的技术措施，以期实现对复杂能谱γ射线的宽谱衰减功能，为开发新型高性能柔性辐射防护材料提供理论依据。

乳胶基射线防护材料可以有效屏蔽γ射线。本项目采用物理球磨法对屏蔽粒子进行了预处理；采用偶联剂对屏蔽填料进行了活化改性；采用聚丙烯酸钠对配合胶乳进行化学增稠，实现了屏蔽填料在胶乳中填充量的增加，最高填充量可达50%。采用物理悬浮法初步证实了屏蔽粒子高填充的可能性。采用层层浸渍法制备了(Gd2O3/WO3/Bi2O3)/NR复合柔性膜。屏蔽性能模拟及试验结果表面，通过元素梯度组合，实现了对较宽范围γ射线（20~100 keV）的宽谱屏蔽，且具有较好的力学性能（拉伸强度、拉断伸长率和硬度），能够应用于低能γ射线防护领域。