Comparative simulated-data study on the low-energy X-ray shielding performance of micro- and nano-sized Bi2O3-filled PMMA composites

Abstract

ABSTRACT This work evaluates micro- and nano-sized bismuth oxide fillers in poly(methyl methacrylate) (PMMA) composites for low-energy X-ray shielding. Eleven material formulations were examined: neat PMMA and PMMA/Bi2O3 composites containing 10, 20, 30, 40, or 50 wt% filler in either micro- or nano-sized form. Seven photon-energy points from 20 to 100 keV and sheet thicknesses of 0.05–1.00 cm were assessed. The composition-based attenuation baseline was obtained from XCOM-style mixture calculations; micro/nano differences were explored only as bounded dispersion, packing, and agglomeration scenarios applied outside XCOM. Under these assumptions, the nano 50 wt% scenario produced a 60 keV radiation protection efficiency of 58.1% at 2 mm, compared with 53.4% for the corresponding micro scenario and 4.1% for neat PMMA. Multi-factor ANOVA showed that thickness, energy, and filler loading dominated the response, with partial eta-squared values of 0.890, 0.785, and 0.713, respectively, whereas the size-class main effect was smaller. The results provide screening hypotheses for formulation selection; they do not constitute experimental evidence that particle size changes intrinsic XCOM coefficients or that the proposed composites outperform certified shielding products.