Porosity and Structural Integrity of Tin-Polydimethylsiloxane (PDMS) Composites for Radiation Shielding Application

Abstract

Ionizing radiation benefits medical treatments and diagnostics. However, it also poses significant health risks, such as from the scattering radiation and unintended exposure. Lead is a common shielding material used for its excellent gamma ray attenuation performance, but it presents ergonomic and environmental challenges. This study assesses the structural and potential radiation absorption properties of the tin-polydimethylsiloxane (PDMS) composites. The composites were fabricated with different metal concentrations and tested for radiation protection efficiency (RPE), structural characteristics, chemical structure, and porosity. Gamma-ray spectroscopy was used to characterize radiation, with Cd-109 as a primary source. Pure tin/PDMS (PT) had the highest RPE compared to copper-tin alloy/PDMS (TA) and copper-tin alloy-pure tin/PDMS (PA), owing to its high atomic number and low porosity. Structural and chemical investigations, including FESEM and FTIR analysis, validated the composites' homogeneity and chemical bonding. The porosity of the composite is evaluated using ImageJ analysis. The results highlight that each composite's porosity increase as the composition of metal filler increases. However, radiation attenuation capabilities more affected by the atomic number of the metal used and metal filler compositions within the composites. Porosity analysis revealed that PT had the lowest porosity among the composites, which may contribute to its superior shielding efficiency. Conversely, TA and PA showed lower atomic number and higher porosity, which disrupted their structural integrity and may reduce photon attenuation. Therefore, methods such as hot pressure, degassing, or vacuum procedures are suggested to reduce the porosity and enhance the radiation shielding within the composites.