Effect of Bi2O3 nanostructures on X-ray shielding, thermal, mechanical and biological properties of PVC polymer nanocomposites

The effect of Bi2O3 nanoparticles and nanowires as fillers in flexible PVC composites was investigated on the shielding properties against X-ray radiation at radiodiagnostic energies (50-129 kV). The PVC composites were gamma radiation cross-linked at 75 kGy. Materials were characterized by thermal analyses, and microstructure studied by SEM. The evaluation involved attenuation measurements and toxicity through cell viability assay. The mechanical properties and toughness were highly improved, according to DMA results, and the TGA analysis shows a small influence of the Bi2O3 nanostructures in the dehydrochlorination reaction of PVC during its thermal decomposition. Moreover, SEM images show a uniform distribution of the Bi2O3 nanostructures in the PVC matrix. Attenuation measurements showed low levels of X-ray transmission for PVC composites with 50 %wt of Bi2O3 and a mass attenuation coefficient greater than those reported for lead in the energy ranges studied, which is an improvement with the use of Bi2O3 NWs. In addition, PVC composites show low HVL and TVL values, making them feasible for the attenuation property. Density measurements show that the composites are lighter than lead. No-toxicity was observed for these composites through cell viability assay. Therefore, the investigated PVC composites are suitable for preparing new radiation-attenuating materials using Bi2O3 NWs.