Mechanical and gamma radiation shielding properties of natural rubber composites: effects of bismuth oxide (Bi₂O₃) and lead oxide (PbO)

ABSTRACT

This work aims to compare the performance between natural rubber (NR) composites with lead oxide (PbO) and bismuth oxide (Bi₂O₃) as shielding fillers for gamma radiation shielding applications. Modulus at 100% elongation, tensile strength, elongation at break, hardness and a specific gravity of the NR composites were investigated. The results indicated that NR/Bi₂O₃ and NR/PbO composites have no significant difference in terms of modulus and hardness values, while the NR/PbO composite exhibited better tensile strength and specific gravity than that of NR/Bi₂O₃ composite. However, NR/Bi₂O₃ composite exhibited better performance in oil resistance and thermal stability than the one with PbO. Gamma radiation shielding properties including mass attenuation coefficient (${\mu }_m$), effective atomic number (Z_eff), effective electron density (N_e) and half-value layer (HVL) have also been studied. It is seen that both the composites exhibited better radiation shielding properties. Furthermore, the radiation properties were in good agreement with the calculated theoretical values. In addition, both the composites of NR with PbO and Bi₂O₃ particles showed excellent radiation shielding properties compared to neat NR as well as commercially available materials including window, ordinary concrete and haematite-serpentine. The material developed in the present investigation can be used as efficient flexible radiation shielding materials. However, lead (Pb) is not suitable to use as a radiation shielding material due to its toxic nature to the human and the environment. Therefore, NR with Bi₂O₃ is an appropriate choice for producing novel wearable radiation shielding materials to manufacture gloves, aprons, rubber underwear and other wearable materials.

KEYWORDS:

• Natural Rubber Composites
• bismuth oxides
• lead oxide
• radiation shielding
• gamma-ray
• flexible shielding materials

Acknowledgments

The authors gratefully acknowledge the National Research Council of Thailand (NRCT), Innovative Multidisciplinary Research in Medical Device Project (Grant no. SCI6101034b) for financial support under the supervision of Prof.Dr.Supayang Voravuthikunchai. A part of the funding from rubber product development group (RPD) is also appreciated for supporting Sililak Intom to undertake research exchange at Center of Excellence in Glass Technology and Materials Science (CEGM), Rajabhat Nakhon Pathom University and the Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University. This research work was partially supported by Chiang Mai University. J. Kaewkhao would like to thanks National Research Council of Thailand (NRCT) and Nakhon Pathom Rajabhat University for supporting this research. Discussion with the research team on different concepts about the background was also beneficial to execute this work.

Disclosure statement

No, potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Research Council of Thailand (NRCT), Innovative Multidisciplinary Research in Medical Device Project [SCI6101034b]; A part of the funding from Prince of Songkla University through Rubber Product and Innovation Development Research Unit [SCIRU63002]and Natural Rubber Innovation Research Institute [SCI601063s].