Green synthesis and characterization of Bi₂O₃ nanoparticles as outstanding filler in polyester for radiation...

In this work, Bismuth oxide nanoparticles (Bi₂O₃ NPs) were prepared by green synthesis method as cost effective and ecofriendly method using olive leaves extract. The successful preparation of nanoparticles was confirmed using IR and XRD. The Bi₂O₃ NPs were used in preparation of unsaturated polyester nanocomposites with different ratios (1, 5, 10, and 20 wt%). The shielding properties of these composites were studied against gamma radiation with different energies emitted from different radioactive sources (59.5, 661.7, (1173 and 1333) keV from Am-241, Cs-137, and Co-60 in series) since different parameters were measured. The results showed that LAC and RSE% increased and HVL and TVL decreased with increase of Bi₂O₃ NPs ratio. The 20 wt% nanocomposite sample has highest LAC values among all samples where it has LAC values of 1.668, 0.134, 0.094, and 0.088 cm^- 1 at 59, 661, 1173, and 1333 keV, respectively. On other hand, pure unsaturated polyester has lowest values where it has LAC values of 0.250, 0.105, 0.078, 0.075 cm^- 1 at 59, 661, 1173, and 1333 keV, respectively. Also, addition of Bi₂O₃ NPs improves thermal properties of the composites where the 20 wt% sample shows 10% weight loss only after 326 °C compared to 247 °C for pure polyester. On other hand, the mechanical properties of unsaturated polyester were negatively affected where compressive strength decreased from 10 to 4.94 MPa with 20 wt% addition percent.