Fabrication and characterization of the hybrid composites of tin (SN)-polydimethylsiloxane (PDMS) against gamma rays

Healthcare workers remain at risk of occupational radiation exposure despite strict safety guidelines and the routine use of personal protective equipment (PPE), with cumulative low-dose exposure linked to increased cancer risk. Although lead-based PPE is highly effective for gamma-ray attenuation, its excessive weight, toxicity, ergonomic burden, and environmental hazards limit long-term usability and safety. The development of lightweight, flexible, and non-toxic alternatives to traditional lead-based radiation shielding materials has gained increasing interest, particularly for medical and industrial applications. This study focuses on the fabrication and evaluation of polydimethylsiloxane (PDMS)-based composite materials reinforced with pure tin and copper tin alloy fillers as potential lead-free shielding solutions. The composites were prepared using a mixing method, followed by curing at an optimized temperature of 100°C to ensure proper solidification and mold removal. Three groups of samples including pure tin (PT), tin alloy (TA), and pure tin mixed with copper tin alloy (PA) were fabricated and characterized. Field Emission Scanning Electron Microscopy (FESEM) revealed that PT samples exhibited uniform dispersion of tin particles with strong adhesion to the PDMS matrix, while TA and PA samples showed less compact distribution and poor matrix bonding, especially with spherical copper particles. X-ray diffraction (XRD) analysis confirmed the presence of crystalline β-Sn in pure tin samples, Cu6Sn5 in copper tin alloy composites, and an amorphous pattern in the PDMS matrix, reflecting distinct phase formations influenced by metal composition. Fourier Transform Infrared (FTIR) spectroscopy confirmed no new chemical bonds were formed between the PDMS and metallic fillers, indicating purely physical interactions. Gamma-ray spectroscopy was used to measure shielding properties through key parameters such as Mass Attenuation Coefficient (MAC), Linear Attenuation Coefficient (LAC), Half-Value Layer (HVL), Tenth-Value Layer (TVL), Mean Free Path (MFP), and Radiation Protection Efficiency (RPE) across 122.1- 1332.5 keV. The PT6 consistently demonstrated superior performance with the highest RPE (86.92%), MAC (0.84 cm2 g-1) and LAC (3.77 cm-1) values and the lowest HVL (0.18 cm), TVL (0.61 cm), and MFP (0.27 cm) values, indicating enhanced gamma-ray attenuation. The PA6 group performed better than TA6, with intermediate values for RPE (68.87%), MAC (0.38 cm2 g-1), LAC (2.08 cm-1), HVL (0.33 cm), TVL (1.10 cm), and MFP (0.48 cm) values suggesting that incorporating pure tin into copper tin alloy-filled composites can improve overall shielding efficiency. Moreover, PT6 and PA6 has lead equivalent of 0.48cmPb and 0.38 cmPb at 356 keV, respectively. In conclusion, PT6 composites show promising potential as sustainable, efficient, and lead-free radiation shielding materials for low energy radiation, meanwhile mixture of metal (PA6) proved to give better radiation attenuation at high energies radiation, offering improved protection while reducing environmental and health concerns associated with traditional materials.