Comparative X-ray Shielding Properties of Single-Layered and Multi-Layered Bi2O3/NR Composites: Simulation and Numerical Studies

Arkarapol Thumwong; Jitsuna Darachai; Kiadtisak Saenboonruang

doi:10.3390/polym14091788

Comparative X-ray Shielding Properties of Single-Layered and Multi-Layered Bi₂O₃/NR Composites: Simulation and Numerical Studies

Polymers (Basel). 2022 Apr 27;14(9):1788. doi: 10.3390/polym14091788.

Authors

Arkarapol Thumwong¹, Jitsuna Darachai², Kiadtisak Saenboonruang^{3

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Affiliations

¹ Department of Materials Science, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
² Department of Engineering Physics, Tsinghua University, Beijing 100084, China.
³ Department of Applied Radiation and Isotopes, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
⁴ Kasetsart Research and Development Institute, Kasetsart University, Bangkok 10900, Thailand.
⁵ Specialized Center of Rubber and Polymer Materials in Agriculture and Industry (RPM), Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
⁶ Special Research Unit of Radiation Technology for Advanced Materials, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.

Abstract

This work theoretically compared the X-ray attenuation capabilities in natural rubber (NR) composites containing bismuth oxide (Bi₂O₃) by determining the effects of multi-layered structures on the shielding properties of the composites using two different software packages (XCOM and PHITS). The shielding properties of the single-layered and multi-layered Bi₂O₃/NR composites investigated consisted of the transmission factor (I/I₀), effective linear attenuation coefficient (µ_eff), effective mass attenuation coefficient (µ_m,eff), and effective half-value layer (HVL_eff). The results, with good agreement between those obtained from XCOM and PHITS (with less than 5% differences), indicated that the three-layered NR composites (sample#4), with the layer arrangement of pristine NR (layer#1)-Bi₂O₃/NR (layer#2)-pristine NR (layer#3), had relatively higher X-ray shielding properties than either a single-layer or the other multi-layered structures for all X-ray energies investigated (50, 100, 150, and 200 keV) due to its relatively larger effective percentage by weight of Bi₂O₃ in the composites. Furthermore, by varying the Bi₂O₃ contents in the middle layer (layer#2) of sample#4 from 10 to 90 wt.%, the results revealed that the overall X-ray shielding properties of the NR composites were further enhanced with additional filler, as evidenced by the highest values of µ_eff and µ_m,eff and the lowest values of I/I₀ and HVL_eff observed in the 90 wt.% Bi₂O₃/NR composites. In addition, the recommended Bi₂O₃ contents for the actual production of three-layered Bi₂O₃/NR composites (the same layer structure as sample#4) were determined by finding the least Bi₂O₃ content that enabled the sample to attenuate incident X-rays with equal efficiency to that of a 0.5-mm lead sheet (with an effective lead equivalence of 0.5 mmPb). The results suggested that the recommended Bi₂O₃ contents in layer#2 were 82, 72, and 64 wt.% for the combined 6 mm, 9 mm, and 12 mm samples, respectively.

Keywords: Bi2O3; X-ray shielding; multi-layered structure; natural rubber; simulation.

Grants and funding

FF(KU)25.64/Kasetsart University Research and Development Institute (KURDI)