Synergistic effect of nano‐bentonite and nanocadmium oxide doping concentrations on assembly, characterization, and enhanced gamma‐rays shielding properties of polypropylene ternary nanocomposites

Abstract

It has been confirmed from an experimental, as well as a theoretical, standpoint that metal oxide polymer nanocomposites (MPNCs) represent a new category of advanced materials effective in radiation shielding. In this study, novel (PP/CdO‐NPs‐NBent) ternary nanocomposites were designed, based on doping polypropylene (PP) with two different nanofillers, namely cadmium oxide nanoparticles (CdO‐NPs) and nano‐bentonite (NBent), to function as promising alternatives for γ‐ray shielding. The PP/(x)CdO(40‐x)NBent nanocomposites samples for x = 0.0, 10.0, 20.0, 30.0, and 40.0 wt% filling concentration were fabricated using the compression molding technique. The surface morphology of the nanoparticles, as well as the corresponding nanocomposites, along with their structural and thermal characteristics was studied using TGA, XRD, SEM, and FT‐IR. A NaI detector was used along with different γ‐ray photon energies (356.01, 661.66, 1173.23, and 1332.50 keV) to measure the mass attenuation coefficient of the nanocomposites being studied, as a function of the percentage of both CdO‐NPs and NBent NPs. In order to verify the applicability of classic “mixture role” on mass attenuation coefficient of anisotropic composites, theoretical mass attenuation coefficient at different photon energies was calculated using XCOM software based on the weight fraction and mass attenuation coefficient of each constituent element among PP/CdO‐NPs‐NBent nanocomposites. The results indicated that the mass attenuation values of the studied nanocomposites are in the same line with results of XCOM simulation code at all the selected range of γ‐ray photon energies. The mean free path, the half value layer, the effective electron density, and the effective atomic number were also calculated to find out the radiation shielding characteristics of the new nanocomposites. Based on the results obtained, it was proven that the addition of CdO‐NPs to the nanocomposites elevated their mass attenuation coefficient, effective atomic number, and effective electron density more than the addition of NBent. The achieved results revealed that the NC2 nanocomposite sample with 40.0 wt% CdO‐NPs had the highest values for mass attenuation coefficient (0.1283 ± 0.96 at 356.01 keV), effective electron density (3.941 ± 0.15 at 356.01 keV), and effective atomic number (41.84 ± 0.34 at 356.01 keV) and the smallest values for half value layer (2.3941 at 356.01 keV) and mean free path (3.3096 at 356.01 keV). As such, it is this nanocomposite that is best at attenuating γ‐rays of all the nanocomposites tested. Highlights Polypropylene was doped with nanoparticles of CdO and bentonite as nanofillers. The developed nanocomposites (PP/CdO‐NPs‐NBent) were characterized. The bulk densities increased from 1.641 ± 0.72 to 4.034 ± 0.45 g/cm³. μ_m, Z_eff, N_el, HVL, and MFP were measured vs (wt%) of CdO‐NPs and NBent. The assembled (PP/CdO‐NPs‐NBent) was found highly protective against γ‐rays.