الفهرس 
Chapter (1) Introduction and literature surveyOnly 14 pages are availabe for public view
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Abstract
Nowadays there is an increase in the usage of gamma-ray emitting isotopes in industry, medicine, and agriculture. So, it is now necessary to study the shielding properties of various materials for technological and biological importance. There is always a need to develop materials, which can be used under harsh conditions of nuclear radiation exposure and can act as shielding materials. Polymer composites could be used in the medical field as clothing to protect patients and the operating personal from exposure to nuclear radiation during diagnostic treatment or imaging in hospitals and to protect personnel working in the vicinity of radiation sources. Polymer composites are going to replace the ordinary shielding materials (concrete shields and developed glass) because of their great properties such as elasticity, lightweight, and durability. These properties can be modified significantly by changing the composition and adopting variations in preparation techniques. During recent years, there are increasing interests in the synthesis, structure, and physical properties of polymer composites filled with heavy metal oxide due to their high density, and good shielding from gamma rays.
In this study, the polymer blend acrylonitrile-butadiene/styrene-butadiene rubber filled with PbO with different concentrations (20, 40, 60, 80, and 100 phr) were prepared as a flexible radiation shielding material. The gamma-rays attenuation properties were carried out using a sodium iodide (NaI) detector using 232Th radioactive source. The attenuation coefficients and half-value layer were evaluated. The distribution of the filler within the polymer matrix was studied using scanning electron microscopy. The prepared polymer composites were characterized by X-ray diffraction technique to recognize the structural phase of the composites. The mechanical properties of the composites were tested. The tensile strength of the composites was found to be enhanced in the presence of the lead oxide as filler. The hardness of polymer composites is increased linearly by increasing lead oxide concentration. Attenuation results reveal that the shielding efficiency increases with the increase of the filler concentration and are comparable to those of the conventional lead-polymer shielding materials. Hence, the composites filled PbO can be used for gamma-ray shielding applications. This work aims at using polymer composites as window frames, cable insulating materials and jackets for workers for all radioisotope laboratories to resist gamma radiation. So, a good shielding material that has shielding ability and should be a good insulator as well. The polymer composites which have been prepared to contain Lead oxide, which has a high atomic number, one may expect a large value of electrical conductivity. The optimum sample S2 of 40 phr was subjected to gamma irradiation at doses from 10 up to 100 kGy. It was found that the irradiation dose up to 20 kGy causes an increase in the tensile strength and hardness.