聚丙烯酸铅辐射防护材料的制备及性能研究

The synthesis of polyacrylic acid lead as radiation-protection composite materials and its radiation shielding properties

采用化学接枝聚合法制备了聚丙烯酸铅辐射防护材料,利用傅里叶变换红外光谱仪(FT-IR)和扫描电镜(SEM)对其结构进行了分析,并利用多道γ谱仪测量了其屏蔽率.利用EGSnrc软件,通过蒙特卡罗模拟,理论计算了防护材料的屏蔽率,讨论了引入样品前后,注量和剂量的变化规律.结果表明:制备的防护材料具有优良的屏蔽性能,其屏蔽效果与射线能量有关.在纯空气介质中,注量和剂量的变化均与粒子能量相关,注量随深度成不连续的阶梯分布,梯高相等,梯宽逐渐变窄,剂量随深度缓慢增加.样品引入后,在空气介质区域,注量和剂量的变化不再与能量相关,而与样品的厚度有关.样品介质区域和空气介质区域的注量都成非线性变化,注量和剂量的变化率在样品与空气分界处,出现了明显的转折.

Polyacrylic acid（PAA） lead was successfully prepared as radiation-protection materials via graft copolymerization route.The product was characterized and analyzed with Fourier transform infrared spectroscopy（FT-IR） and scanning electron microscopy（SEM）. Gamma energy-spectrum measurement was carried out to evaluate its radiationshielding properties.EGSnrc user code was also employed to theoretically simulate its above properties based on Monte Carlo method and analyze the influences of this material on the fluence and dose in the detecting area.The results revealed that this composite material has excellent radiation-shielding ability and this ability decreased with the increase of γ-ray energy.According to our theoretical simulation,in pure air,the change of fluence is discontinnous and looks like a ladder whose step width beomes narrower grdually and the dose increased slowly whith depth.When the sample was put into the air,in the air medium area,the changes of fluence and dose were no longer related with ray energy but with the sample thickness,while in the sample medium area,the changes of fluence and dose were not rectilinear and the rate of changes makes an obviously turn at the boundary between the sample and air.