【作者】 张瑜；

【导师】 戴耀东；

【作者基本信息】 南京航空航天大学 ， 核技术及应用， 2011， 硕士

【摘要】 高分子材料特别是先进树脂基复合防护材料具有质轻、易成型、价格低廉等优点,已在航天工程、核动力装置、医疗器械方面展现出广阔的应用前景。本文利用金属功能粒子对高分子材料进行改性,使所制备的复合材料具备良好的综合性能,开展了复合材料制备、结果表征讨论、性能测试和理论模拟分析等方面的工作。主要研究内容与成果总结如下:(1)采用γ辐射接枝聚合法制备了纳米聚丙烯酸铅/环氧树脂辐射防护材料并对其微观结构、力学性能及屏蔽性能进行了测试分析。结果表明:复合材料为两相聚合物共混体系,其分散形态呈明显的海-岛结构,其韧性和强度较纯环氧树脂有明显提高。复合材料具有较高的质量吸收系数,是一种屏蔽性能良好的轻质材料。(2)采用化学接枝聚合法制备了聚丙烯酸铅辐射防护材料并对其组成结构进行了表征、对其辐射屏蔽性能进行了实验测试。结果表明,样品具有良好的辐射屏蔽性能。基于蒙特卡洛方法,用EGSnrc软件对材料中的辐射剂量与注量分布规律进行了模拟计算。结果显示:在辐射场区域内引入适当形状的此种材料,可以有效改变辐射场的分布。(3)采用固化成型的方法制备了五种PbO/Er2O3 /E-51医用加速器放射治疗新型铅挡板材料。利用BEAMnrc/DOSXYZnrc软件计算了其百分深度剂量和离轴比。结果表明:使用新挡板材料会在水箱表面发生更多的能量沉积事件。最大剂量和最大剂量深度与样品中铒、铅元素的浓度相关。样品ⅴ的最大剂量深度为0.2—0.7cm,非常适合作为皮肤和浅表肿瘤的铅挡板材料。更多还原

【Abstract】 Polymers have the character of low density, easy molding and low cost. The polymer especially the advanced resin-based composites materials have widely prospect in aerospace, nuclear power station and radiotherapy instruments. This paper focuses on the preparation, characterization and simulation of radiation shielding polymer modified by the metal functional particles. The mainly contents and typical results were summarized as follows:(1) Nano-poly (lead acrylate) epoxy resin was successfully prepared via graft copolymerization route induced byγirradiation. The product was characterized and analyzed with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). All results reveal that these composite materials have a sea-island biphase structure and exhibit better mechanical properties than the pure epoxy resin. Theγ-ray mass absorption coefficient of this material was 0.060 cm2 g-1 under 1.33 MeV, which reveal the product has good radiation-protection characterizations.(2) Poly-acrylic acid (PAA) lead was successfully prepared via graft copolymerization route. The structure and radiation shielding properties of as prepared samples were characterized and analyzed. All results reveal that this composite material has excellent radiation-shielding ability. EGSnrc code was also employed to analyze t the fluence and dose in the detecting area in this material. According to the theoretical simulation, this material can change the original distribution of the radiation dose.(3) Five kinds of PbO/ Er2O3/E-51 samples which could be used as the cerrobend block in the electron beam radiotherapy treatment were prepared successfully by a solidified forming approach. The central axis depth dose and off-axis dose profiles in the water phantom were calculated using BEAMnrc/DOSXYZnrc code. The results show that more energy deposition events are induced by low energy electron beams in the surface of the water phantom. The maximum dose (Dm) and the depth at the maximum dose (Rm) are linear dependent with the weight fraction of erbium and plumbum element in the sample. The sampleⅴwith the Rm of 0.2—0.7cm is very satisfactory for serving as the block in the skin and superficial tumors radiotherapy treatment.更多还原