Light weight, easy formable and non-toxic polymer-based composites for hard x-ray shielding: A theoretical and experimental study

Composite lightweight materials for X-ray shielding applications were studied and developed with the goal of replacing traditional screens made of lead and steel, with innovative materials with similar shielding properties, but lighter, more easily formed and workable, with lower impact on the environment and reduced toxicity for human health. New epoxy-based composites additivated with barium sulfate and bismuth oxide were designed through simulations performed with software based on Geant4. Then, they were prepared and characterized using different techniques starting from digital radiography in order to test the radiopacity of the composites, in comparison with traditional materials. The lower environmental impact and toxicity of these innovative screens were quantified by Life Cycle Assessment (LCA) calculation based on the ecoinvent database, within the openLCA framework. Optimized mixtures are (i) 20% epoxy/60% bismuth oxide/20% barite, which guarantees the best performance in X-ray shielding, largely overcoming steel, but higher in costs and a weight reduction of circa 60%; (ii) 20% epoxy/40% bismuth oxide/40% barite which has slightly lower performances in shielding, but it is lighter and cheaper than the first one and (iii) the 20% epoxy/20% bismuth oxide/60% barite which is the cheapest material, still maintaining the X-ray shielding of steel. Depending on the cost/efficiency request of the specific application (industrial radiography, aerospace, medical analysis), the final user can choose among the proposed solutions.