Comparative investigation of gamma-ray shielding in WO3 and Bi2O3 modified EPDM rubber composites

A comparative investigation was systematically performed on EPDM rubber composites filled with nano-WO 3 and micro-Bi 2 O 3 at filler loadings of 20, 60, 100 phr (parts per hundred rubber) to evaluate gamma-ray shielding performance at 59–960 keV by experiment and simulation. Experimental results agreed well with NECP-MCX Monte Carlo simulations. Shielding efficiency increased with filler content for both systems, and Bi 2 O 3 exhibited approximately 10% higher shielding efficiency than WO 3 . Quantitative analysis of linear attenuation coefficient (μ), mass attenuation coefficient (μ m ), and half-value layer (HVL) showed that at 59 keV, increasing the filler loading of WO 3 and Bi 2 O 3 from 20 to 100 phr led to μ respective elevation from 0.7664 to 2.6381 cm −1 and from 1.0927 to 4.2342 cm −1 ; and μ m respective elevation from 0.6755 to 1.5430 cm 2 /g and from 0.9606 to 2.4306 cm 2 /g; at 343 keV, μ increased in the range of 0.1095∼0.2409 cm −1 and 0.1302∼0.3125 cm −1 ; and μ m respective elevation in the range of 0.0967∼0.1409 cm 2 /g and 0.1144∼0.1794 cm 2 /g. At a fixed filler loading of 60 phr, as the energy increased from 59 to 960 keV, μ of samples decreased from 2.1397 to 0.0695 cm −1 , μ m from 1.4810 to 0.0484 cm 2 /g, and HVL increased from 0.3239 to 9.9649 cm. Higher filler loadings reduced tensile strength and elongation at break but increased Shore hardness, and WO 3 -filled samples exhibited better mechanical properties.