Radiation shielding performance of CeO₂-reinforced ternary nanocomposites based on biodegradable polymers and...

The development of sustainable polymer-based materials for radiation shielding has attracted increasing interest, particularly for lightweight and flexible applications. In this study, ternary nanocomposites based on poly (hydroxyalkanoate) (PHA), poly (ε-caprolactone) (PCL), and polystyrene (PS) were prepared and reinforced with cerium oxide (CeO₂) nanoparticles (5-15 wt%) to enhance radiation shielding performance. Structural characterization confirmed the preservation of polymer chemical structures and the successful incorporation of crystalline CeO₂, while SEM observations revealed a relatively homogeneous nanoparticle dispersion within the ternary matrix, particularly at intermediate filler loadings. Thermal analysis demonstrated enhanced thermal stability with increasing CeO₂ content, as evidenced by an increase in residual mass from 0.42% for the neat blend to 11.21% for the nanocomposite containing 15 wt% CeO₂, along with a shift of degradation onset temperatures toward higher values. Photon shielding performance was experimentally evaluated in the energy range of 13.37-59.54 keV. The incorporation of 15 wt% CeO₂ increased the mass attenuation coefficient (MAC) from 1.277 to 12.366 cm² g^-1 at 13.37 keV, corresponding to an approximately ninefold enhancement, while significantly reducing the half-value layer (HVL) and mean free path (MFP). Neutron shielding analysis showed a slight decrease in thermal neutron attenuation due to hydrogen dilution within the polymer matrix, whereas fast neutron attenuation and neutron removal cross sections exhibited only minor variations; the fast neutron removal cross section increased modestly from 0.1014 to 0.1047 cm^-1 with 15 wt% CeO₂ addition. Overall, the results highlight clear structure-property-performance relationships in CeO₂-reinforced PHA/PCL/PS nanocomposites, demonstrating their potential as lightweight radiation shielding materials for low energy protection with improved thermal stability and shielding efficiency.