低密度泡沫材料大多存在一定程度的密度不均匀性,这对其后续使用性能将带来不良影响。简述了ICF靶用聚丙烯酸酯泡沫的制备方法,对其密度不均匀性形成机理进行理论分析。在此基础上,改进其制备工艺,控制泡沫密度分布,并利用β射线检测技术,对制备工艺改进前后直径为mm量级的低密度聚丙烯酸酯泡沫柱进行密度分布表征。研究结果表明:改用聚四氟乙烯代替玻璃模具,有利于制得密度分布均匀的泡沫样品;选用最高的紫外光的能量,能促进自由基均匀分布,从而最终能够提高泡沫的密度均匀性。采用β射线对密度范围为10～100 mg·cm-3的TMPTA泡沫的密度均匀性进行表征,结果表明:随着泡沫密度的降低,密度均匀性越低,对制备工艺要求越高。

The density non-uniformity exsiting in most low-density foams will affect performance of the foams. The trimethylolpropane trimethacrylate(TMPTA) foam targets were prepared and controlling methods of the foams,density uniformity were explored together with its forming mechanism. It has been found that the UV-light with high intensity can improve the distribution uniformity of the free radicals induced by UV photons in the solvents,thus improve the density uniformity of the foams. In addition,container wall would influence the concentration distribution of the solution, which affects the density uniformity of the foams. Thus,the UV-light with high intensity was chosen together with polytetrafluoroethylene molds instead of glass molds to prepare the foams with the density non-uniformity less than 10%. β-ray detecton technology was used to measure the density uniformity of the TMPTA foams with the density in the range of 10 to 100 mg·cm-3, and the results show that the lower the foam density is,the worse the density uniformity is.