Loading of rubber nanocomposites by lead nanoparticles for gamma radiation shielding

The goal of this research is to create protective shields that can be used to protect healthy tissues from the harmful effects of gamma rays by adding lead nanoparticles (Pb-NPs) to styrene-butadiene rubber. The basic principle is to attenuate the gamma-ray photons emitted by a Cesium source (Cs¹³⁷⁾ with energies of 0.663, 1.173, and 1.462 MeV. The shielding properties after adding 50, 100, 200, and 300 parts per hundred parts of rubber (phr) of lead nanoparticles were examined. The results showed that the increases in the mean free path parameter (MFP) at a source energy of 1.462 MeV were 83.51% and 76.19% for SBR1 (without Pb-NPs) and SBR5, respectively. In addition, with increasing thickness of the shielding materials and Pb-NP loading, the mass attenuation coefficient (µm) decreased, and the half-value layer (HVL) and tenth value layer (TVL) increased. At the same time, the half-value and tenth-value layers increased by 86.52% and 76.2%, respectively, for SBR1 and SBR5 at a source energy of 1.462 MeV. Field emission scanning electron microscopy (FE-SEM) images showed good dispersion and homogeneity of these particles in the rubber matrix, and few agglomerations occurred with increasing lead loading. The swelling ratio decreased by 199%, and the volume fraction of rubber and cross-link densities were increased by approximately 7.1% and 14%, respectively. The addition of lead nanoparticles led to improved the crystalline properties.