New Generation of 2D Materials for Ionizing Electromagnetic Radiation Shielding Applications
Date
2022
Authors
Yu, Le
Editors
Advisors
Losic, Dusan
Journal Title
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Thesis
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Abstract
The hazards from the use of X-ray have been recognized by International Committee on Radiological Protection (ICPR), showing that it is detrimental for human health, including the damage to human cells and is a carcinogenic hazard. The use of X-ray shielding apparel is therefore of great significance to protect workers from risk of excessive exposure towards harmful X-ray. Lead (Pb) has been used as an ideal radiation shielding material, owing to its high Z at 81 and high density of 11.3 g/cm3, which is commonly for sale on the market. However, the concerns have been growing recently that using Pb has caused safety and health issues. The toxicity, heaviness, and inflexibility of the Pb-based garments pose a great risk to practitioners, which can harm their biochemical system. The substitution of Pb is thus momentous for the development of lightweight, non-toxic, and Pb-free X-ray shielding materials, where several high-Z metals (including bismuth (Bi), tungsten (W), and barium (Ba), tin (Sn), and antimony (Sb)) and their derivates were explored. The aim of this thesis is to develop a new generation of lightweight, Pb-free, and highly efficient materials using a series of nanosized and layered 2D materials with their laminated structures and composites. Three key aspects are addressed in this thesis: firstly, the synergistic effect of the particle size and morphology on X-ray shielding performance have been investigated, showing that the nanomaterials with higher surface-to-volume ratio provide a significant effect on X-ray attenuation. Adapted this idea, successful synthesis of bismuth titanate (BTO) nanocomposite provides superior X-ray shielding ability (0.35 mm Pb equivalent attenuation). Secondly, development of the 2D layered material using few-layer molybdenum MoS2 provides an insight study for superior low-energy X-ray shielding application. Further, the design of the laminated 2D layered structure composed of few-layer MoS2, antimonene, Mxene and their heterolaminates combinations (MoS2 +Mxene) shows a promising enhancement for low-energy X-ray shielding, which could be a new radiation shielding technology. Thirdly, the addition of graphene and hexagonal boron nitride (hBN) has a significant impact on reinforcement of polymer-based composites, leading to improved X-ray shielding ability of MoS2 nanocomposite. On the other hand, the laminated polymerbased composite with the few-layer antimonene exhibits enhanced X-ray shielding ability. The superior X-ray shielding performance obtained from these studies suggests that these lightweight, non-toxic, and environmentally friendly materials could pave the development of a new generation of highly efficient Pb-free shielding materials, which is urgently needed across the broad sectors.
School/Discipline
School of Chemical Engineering and Advanced Materials
Dissertation Note
Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering and Advanced Materials, 2022
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