###### Abstract  
The most important factors in the manufacture of shielded sheets are shielding ratio, light weight, and tensile strength. The base material should provide a light-shielding film with strong physical shock resistance, while maintaining the shielding ratio of lead. Therefore, we studied the correlation between the porosity during the mixing process and the maintenance of the shielding film characteristics. Changes in the shielding ratio can be predicted according to the properties of materials such as polymeric silicon and tungsten oxide. Further, their tensile strength and porosity may change depending on the content of the material. Experiments were carried out for each substance based on the shielding ratio with respect to the processing conditions. For a shielding film using barium sulfate (BaSO4) and polymeric silicon, increasing the porosity by the removal of air in the same manufacturing process resulted in a tensile strength of 6.4 MPa at 22% porosity. For tungsten oxide (WO3), the tensile strength was 10.5 MPa at a porosity of 12%, and for a 0.6 mm sample, the shielding performance was very similar to 0.21 mm of Pb. The porosity during the manufacturing process affected the tensile strength and shielding performance, which were significantly different for each shielding material. radiation protection; radioactive material; X-ray; radiation dose; shielding film +
Footnote †: journal: Applied  
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[PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], S.-  
owing to its outstanding processability and overall safety when used as a base polymer with high hydrophobicity [8; 9]. However, problems arising during the compounding process may affect the thickness, strength, and flexibility of the material, resulting in mass-production problems [10]. The strength and hardness (mechanical properties) of the RSF generated in these \"environmentally friendly shielding material and polymeric silicon\" blending processes are very important for commercialization. Porosity has a direct relationship with the change in the mechanical properties of the RSF during the \"shielding material and polymer resin\" blending and mold fabrication processes. Porosity is the percentage void space of the total volume of fillers and granules [11; 12]. This is a very important condition for determining the shielding ratio in the RSF fabrication process. The manufacturing method should be upgraded by lowering the thickness and improving the shielding ability, rather than increasing the amount of material. A laminate processing method evenly disperses particles or, when repeated, fabricates multilayered, multi-gate structures [13; 14; 15]. This method of production uses an empirical manufacturing approach rather than a quantitative one. However, there are no specific studies on the quantitative effect of the mixing ratio of the materials, on their porosity, tensile strength, or shielding performance. In particular, there is no general study on the porosity, thickness, shielding performance, and tensile strength of the RSF produced by combining bismuth oxide (Bi\({}_{2}\)O\({}_{3}\)), tungsten oxide (WO\({}_{3}\)), and barium sulfate (BaSO\({}_{4}\)), which are the most commonly used shielding materials with polymer resins. There is also no known difference in the final RSF product. In light of the above, we quantitatively analyzed the effects of environmentally-friendly shielding materials such as Bi\({}_{2}\)O\({}_{3}\), WO\({}_{3}\), and BaSO\({}_{4}\) on the same polymeric silicone resin, specifically with regard to differences in formulation ratio, porosity, tensile strength, and shielding performance. First, the porosity was observed with an electron microscope capable of magnifying the pores, and influence factors were summarized using formulas. The tensile strength and shielding performance were tested based on the thickness of the RSF and compared with the lead equivalent of shielding performance.