DEVELOPMENT OF NOVEL PMMA NANOCOMPOSITES AS LIGHTWEIGHT SHIELDING MATERIALS FOR GAMMA AND X RADIATION

Abstract

Despite the effective use of ionizing radiation in the medical field, radiation exposure remains a health hazard and poses threats to human life. In turn, this requires the development of radiation shielding materials. A radiation shield is primarily composed of lead due to its physical and mechanical properties, but lead might be toxic in the case of dust on the surface of lead objects. Polymer-based radiation shields can be utilised in the radiation shielding field due to their excellent physical and chemical properties, ease of fabrication, low manufacturing costs, and toughness. Also, their radiation shielding properties can be improved by using high atomic number fillers. The development of lead-free poly(methyl/methacrylate) PMMA-based nanocomposites reinforced with the following nanoparticles is the focus of this study: bismuth oxide magnesium oxide composites (Bi2O₃:MgO), bismuth oxide-silicon oxide composites (Bi2O₃:SiO₂) and magnesium oxide-silicon oxide composites (MgO:SiO₂) for gamma and X-ray shielding. Despite the addition of nanoparticles, PMMA's chemical stability is confirmed by the fourier-transform infrared spectroscopy's (FTIR) lack of new absorption bands in1000–4000cm-1 spectrum. The X-ray diffraction (XRD) with discrete peaks of crystallinity that correspond to Bi2O₃, MgO, and SiO₂ fillers showed that the PMMA matrix was amorphous, indicating a successful composite production. The scanning electron microscopy (SEM) study showed an equal dispersion of the nanoparticles up to 20 weight percent, whereas a tiny lump was seen at higher loadings. The optical properties were investigated with the help of a UV–Visible Spectrophotometer. The results for the optical properties showed that when the nanocomposites content was increased in the PMMA matrix the Urbach energy (∆E), refractive index (n) increased, while the energy optical band gap (Eopt) registered a decrease in both electron transition direct and indirect. Pure PMMA had a density of 2.72 g/cm3, while sample PMMA/25 wt% Bi2O3:MgO had a density of 3.63 g/cm3. Due to increased photon-matter interaction, the optical band gap of the highly loaded composites increased from 4.64 eV in the pure PMMA to 5.56 eV. At 662 keV, the linear attenuation coefficient (LAC), one of the radiation shielding tests, rose from 0.20 cm-1 for the pure PMMA sample to 0.28 cm-1 for PMMA/25 wt% Bi₂O₃:MgO, whereas the corresponding HVL dropped from 3.36 cm to 2.45 cm. Among other samples, PMMA/25 weight percent Bi2O3:MgO had the best shielding capability, with a radiation protection effectiveness value near that of lead at a diagnostic range. Focus on surface functionalization of the nanoparticles should be examined in future studies as well as multilayer composite designs, and full biocompatibility and mechanical assessments for wearable radiation shielding applications.