Preparation And ?-rays Shielding Property Of Nano And Micro-lead Tungstate/nature Rubber Composites

Flexible ?-rays protective materials which have the ability to protect the ?-rays and are capable of bending and stretching,have been used in national defense industry,nuclear energy,medical hygieneand many other wearable radiation protection products.However,the research progress has been slowdue to the limitations of application requirements and theories.At present,the ?-rays absorption coefficient of such materials is generally low,resulting in bulky and uncomfortable to wear.With the rapid development and application of nuclear science and technology,nuclear activities are more frequent and the demand for wearable radiation protection products is even greater;after the Fukushima nuclear accident,people have higher requirements for the performance of radiation protection products.Therefore,it is very important to improve the absorption coefficient of y-rays in flexible materials.In view of this,the research work on the synthesis of leadtungstate(PbWO4,PWO)particles with ?-rays protection function,surface modification and preparation of PWO/NR composites were carried out,And the flexible materials with excellent ?-rays protections and mechanical properties.Firstly,PWO/NR radiation protection material was prepared by mechanical blending method using KH570 as modifier,and PWO particles as functional filler.The micro-morphology,mechanical and shielding properties were characterized.The effects of modifier content and PWO particle size on the mechanical properties and y-rays shielding ability of the composites were also investigated.The result showed that the best mass fraction of KH570 was 15%,and the mass attenuation coefficient of the composite materials increased with the increase of the PWO filling amount.Nanoscale PWO/NR composites had better shielding effectiveness and worse hardness than micro-sized PWO/NR composite.According to the comparison of shielding effectiveness about the two kinds of composites,the y-rays shielding efficiency of the nanocomposites increased by 18-31%,indicating that the nanoparticles contribute to the ?-rays attenuation performance of the composites.Secondly,in order to further improve the y-rays protection performance of the material,highly filled PWO/NR composite materialswere obtained by controlling the proportion of nano and micro-PWO particles to adjust the particle size distribution of PWO.The results showed that high-filled nano-PWO particles could enhance the tensile strength and mass attenuation coefficient of the composites.Compared with nanocomposites with the same loading,the volume ratio of nano-PWO to micro-PWO was 4:6 at 0.086 MeV and 0.105Mev.The mass attenuation coefficient reached 3.56cm2/g and 3.89cm2/g respectively,increased by 35.9%and 30.5%,respectively.The screening efficiency increased greatly,the tensile strength only decreased by 3.68MPa,and the Shore hardness decreased.