微米板Sm_(2)O_(3)填料增强HDPE复合材料的制备及中子和伽马辐射屏蔽性能

Preparation of Micron Plate Sm_(2)O_(3)Fillers Reinforced High-density Polyethylene Composites for Neutron and Gamma Radiation Shielding

分别采用合成的Sm_(2)O_(3)(Sm_(2)O_(3)-I)填料与商用Sm_(2)O_(3)(Sm_(2)O_(3)-II)填料制备了Sm_(2)O_(3)/碳化硼(B_(4)C)/高密度聚乙烯(HDPE)复合材料,并用于中子和伽马辐射屏蔽.X射线衍射(XRD)结果表明,Sm_(2)O_(3)-I填料属于立方晶系、体心立方晶格、Ia-3(206)空间群;而Sm_(2)O_(3)-II填料中存在两种物相,一种为单斜晶系、简单单斜格子、C2/m(12)空间群,另一种为立方晶系、体心立方晶格、Ia-3(206)空间群.场发射扫描电子显微镜(FESEM)和比表面积分析结果表明,Sm_(2)O_(3)-I填料微观形貌为带狭缝的微米板结构,其Brunauer-Emmett-Teller(BET)比表面积(SBET)为5.15 m^(2)/g;Sm_(2)O_(3)-II填料中存在由两种物相导致的板状团聚体与无特定形貌团聚体两种微观形貌,其SBET为2.47 m^(2)/g.合成的微米板Sm_(2)O_(3)-I/B_(4)C/HDPE复合材料的熔融温度(T_(p))和屈服应力(σ_(y))分别为140.6℃和22.6 MPa,优于商用Sm_(2)O_(3)-II/B_(4)C/HDPE复合材料.中子和伽马辐射屏蔽测试结果表明,尺寸均一且具有高BET比表面积的微米板Sm_(2)O_(3)-I填料可提高复合材料的中子和伽马辐射屏蔽性能.厚度为15 cm的10%Sm_(2)O_(3)-I/20%B_(4)C/70%HDPE(质量分数)复合材料对^(252)Cf中子源的中子屏蔽率达98.4%,对^(137)Cs伽马源的伽马辐射屏蔽率达71.7%,均高于采用商用Sm_(2)O_(3)-II作为填料的复合材料.

Samarium oxide(Sm_(2)O_(3))/boron carbide(B_(4)C)/high-density polyethylene(HDPE)composites are respectively prepared by using synthesized Sm_(2)O_(3)fillers(Sm_(2)O_(3)-I)and commercial Sm_(2)O_(3)fillers(Sm_(2)O_(3)-II)for neutron and gamma radiation shielding.The X-ray diffraction(XRD)patterns reveal that the phase of Sm_(2)O_(3)-I fillers is a cubic crystal system,body-centered cubic lattices,and its space group is Ia-3(206).However,Sm_(2)O_(3)-II fillers have two phases.One is a monoclinic crystal system,simple monoclinic lattices,and its space is C2/m(12).The other one is a cubic crystal system,body-centered cubic lattices,and the space group is Ia-3(206).Field emission scanning electron microscopy(FESEM)and specific surface area analyses reveal that the micromorphology of Sm_(2)O_(3)-I fillers is micron plate with silt and its Brunauer-Emmett-Teller(BET)specific surface area(SBET)is 5.15 m^(2)/g,while irregularly shaped Sm_(2)O_(3)-II fillers have two kinds of micromorphology caused by the two phases of Sm_(2)O_(3)-II fillers,which are plate-like agglomeration and agglomeration without specific shape,and the SBET of Sm_(2)O_(3)-II fillers is 2.47 m^(2)/g.The melting temperature(T_(p))and yield strength(σ_(y))of the synthesized Sm_(2)O_(3)-I/B_(4)C/HDPE composites are respectively 140.6℃ and 22.6 MPa,which are better than the commercial Sm_(2)O_(3)-II/B_(4)C/HDPE composites.The neutron and gamma radiation shielding tests reveal that the synthesized Sm_(2)O_(3)fillers with even size and high BET-specific surface area can improve the neutron and gamma radiation shielding performance of composites.10%Sm_(2)O_(3)-I/20%B_(4)C/70%HDPE(mass fraction)with a thickness of 15 cm has a neutron radiation shielding rate of 98.4%under the^( 252)Cf neutron source and a gamma radiation shielding rate of 71.7%under^(137)Cs gamma source.