Preparation And Property Of EPDM-based Radiation Protection Materials

EPDM rubber-based protection materials are becoming a focus research because of their low density, easy molding, low cost, high radiation resistant property and accept large amount of filler easily. We mainly conduct a series of experiments and studied the shielding effect and radiation resistance property.Five radiation shielding fillers （PbWO4,Pb3O4,PbO,Bi2O3,Nd2Fe14B） were test for the radiation attenuation properties. Among them Pb3O4 filler exhibits the best radiation shielding performance when the same mass fraction of fillers mixed with EPDM matrix. However, take account of the possible harm to human issue, PbWO4 filler with lower lead ion mobility was selected as experiment filler in next study.The PbWO₄ （PWO）/EPDM radiation protection materials were prepared by mechanical mixing method, in which PWO were used as shielding substance. The microstructure, shielding and mechanical property of the composites were studied, the shielding effects of different content and different size of PWO to gamma energy were investigated. The results shows that the mass attenuation coefficient of composites increases when the content of filler raises and the mass attenuation coefficient decreased with increasing gamma energy. Compared to micro-sized PWO/EPDM composites, the results shows that submicro-sized PWO/EPDM composites has a higher mass attenuation coefficient. According to the shielding effect of two kinds of composites, the mass attenuation coefficient of submicro-sized PWO/EPDM composites is 1-10% higher than that of micro-sized PWO/EPDM composites.The 200 phr PWO/EPDM radiation protection materials were prepared by mechanical mixing method, where different size of PWO were used as shielding substance, EPDM used as matrix, only vulcanizing agent as additives. The composites were irradiated by different radiation dose （0,50,100,150,200 kGy） under air atmosphere and the aging effect of composites was explored. The results shows that when the radiation dose increased, the hydroxyl and carbonyl groups increased, soluble fraction increased as well as the mechanical property deteriorated. Compared to pure EPDM, PWO existed in composites can absorb part of gamma energy, so composites have a relative lower soluble fraction, which can delay the radiation aging process and extend the life of the radiation shielding material.