Preparation And Study Of Flexible Radiation Shielding Composite Materials Based On Methyl Vinyl Silicone Rubber

With the rapid development of nuclear industry and the radiation medical treatment technology, the research on the advanced lead-free flexible radiation shielding materials for personal protection and the flexible materials for additional radiation shielding of nuclear equipment was profoundly significant. In this paper, three kinds of new type of flexible radiation shielding materials were developed, and a series of research work for the performances of composite materials and their influence factors had been carried out.1) For personal radiation protection products demand for new types of flexible lead-free radiation protection materials, the novel, flexible, lead-free X-ray-shielding composites were prepared through mixing process and vulcanized molding process with a high-functional methyl vinyl silicone rubber(VMQ) matrix with W and Bi2O3 as filler materials, and the X-ray shielding properties, morphology observations, mechanical properties, water-vapor transmission performance, and thermal conductivity of composite materials and their influence factors were also studied. Experimental results showed that W/Bi2O3/VMQ materials exhibited better X-ray shielding abilities than the Bi2O3/VMQ composites in the same filler contents; as the filler volume fraction increased, the mechanical properties of the W/Bi2O3/VMQ composites decreased; with increasing filler volume fraction, the average cumulative permeability of the W/Bi2O3/VMQ composites decreased; and W element could efficiently increase the thermal conductivity of the VMQ composites.2) In fire case, the neutron source system and other equipments demand for flame retardant flexible neutron shielding materials, so the new flexible flame-retardant neutron shielding materials were fabricated through powder surface modification process, silicone rubber mixing process, and vulcanized molding process with B4 C, ZB, and hollow bead materials as fillers, and morphology observations, mechanical properties, thermal conductivity, flame retardancy, and neutron shielding properties of composites and their influence factors were also studied. Experimental results showed that surface modification of the fillers apparently improved dispersion in the VMQ matrix; as the filler contents increased, the mechanical properties of composites decreased; addition of hollow beads exceeded 3.5 wt% resulted in higher heat insulation properties of the composites; when ZB content exceeded 12 wt%, the composites reached the hardly flammable material grade; the transmission of neutron for a 2 cm sample was only 47.8 %.3) For the spent fuel storage and transportation equipments demand for flexible radiation resistant neutron / gamma ray shielding materials, the novel flexible radiation resistance neutron and ?-ray shielding materials were fabricated through powder surface modification process, silicone rubber mixing process, and vulcanized molding process with B4 C, PbO, and benzophenone as fillers, and morphology observations, the degree of crosslinking density, mechanical properties, thermal Stability, and neutron and ?-ray Shielding properties and their influence factors were also studied. Experimental results showed that surface modification of the fillers apparently improved dispersion in the VMQ matrix; benzophenone effectively inhibited the cross-linking reaction of VMQ caused by radiation; after irradiation, the tensile strength, elongation at break, tear strength, and flexiblity of the composites decreased, but the composites with BP showed the better mechanical properties; the initial degradation temperatures of the composites containing BP before and after irradiation were 323.6 °C and 335.3 °C, respectively; the transmission of neutron for a 2-mm thick sample was only 0.12, and the transmission of ?-ray with the energies of 0.662 MeV, 1.173 MeV and 1.332 MeV for 2-cm thick samples were 0.7, 0.782, and 0.795, respectively.In this paper, the research work provided an important reference for personal radiation protection and nuclear equipment radiation protection with high performance flexible radiation shielding material. And the technical foundation of higher performance, function stronger, more extensive use of flexible radiation protection materials was laid.