Development of (polyvinyl alcohol/O-carboxymethyl chitosan/PbO) nanocomposites for efficient gamma radiation...

A polymeric blend based on polyvinyl alcohol (PVA) / carboxymethyl chitosan was developed for gamma radiation shielding applications. The nanocomposite films were fabricated using a simple solution casting method, where the readily available nanosized lead oxide PbO particles were dispersed within a polymer matrix composed of PVA, polyvinylpyrrolidone (PVP), and citric acid. The dispersion process was assisted by sonication before crosslinking, ensuring uniform distribution of oxide particles throughout the films. The physicochemical properties of the synthesized nanocomposites were systematically characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis spectroscopy), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), water vapor permeability (WVP), soil burial degradation, and total soluble matter (water absorption) measurements. Gamma shielding performance was evaluated through the determination of linear and mass attenuation coefficients (μ and μ/ρ) at photon energies ranging from 59.53 to 1332 keV, using a NaI (Tl) scintillation detector with standard gamma-ray sources (Am-241, Ba-133, Eu-152, Cs-137, and Co-60). Additional shielding parameters, including half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP), were calculated. The experimental linear and mass attenuation coefficients for the blank sample, which closely matched the theoretical predictions from XCOM, verified the produced films' outstanding gamma radiation shielding capabilities. PbO nanoparticles were incorporated into the chitosan matrix to produce a uniform and compact film structure. HVL, TVL, and MFP, among other computed shielding factors, showed how well the nanocomposites attenuated gamma photons throughout a broad energy range. Furthermore, the structural stability, uniform shape, and environmental degradability of the composites were validated by physicochemical studies. These findings demonstrate that carboxymethyl chitosan/PbO nanocomposite films are attractive options for long-term radiation protection, as they combine efficient radiation-shielding capabilities with other desirable properties. While carboxymethyl chitosan/PbO nanocomposite films show promising radiation shielding efficiency, their long-term stability remains a concern, as partial material degradation may affect their sustained performance.