Two-step hydrothermal synthesis of Gd2O(CO3)2@Bi-MOF/graphene nanoplatelets for enhancing 222Rn and gamma radiation shielding of polymethyl methacrylate-based composites

With the increasing complexity of radiation environments, the development of effective shielding materials against 222 Rn and gamma radiation is critical for ensuring human health and safety. This study utilized a two-step hydrothermal method to synthesize Gd₂O(CO₃)₂@bismuth-based metal–organic frameworks (Bi-MOFs)/graphene nanoplatelets (GBG) composite fillers, followed by melt blending and hot-press molding to develop GBG/polymethyl methacrylate (PMMA) composites aimed at shielding against 222 Rn and gamma radiation. The successful synthesis and structural integrity of the composites were confirmed using various characterization techniques, including x-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. The experimental results indicate that the GBG composite filler exhibits superior enhancement in 222 Rn shielding capabilities, with the 222 Rn diffusion coefficient of GBG/PMMA-20 composites reduced to 1.41 × 10 −13 m 2 /s, a 98.6% decrease compared to pure PMMA (1.04 × 10 −11 m 2 /s). Furthermore, the GBG demonstrates outstanding improvements in gamma-ray shielding performance, with the mass attenuation coefficient of GBG/PMMA-50 reaching 2.70 cm 2 /g for 59.5 keV gamma rays, nearly 16 times higher than that of pure PMMA (0.16 cm 2 /g). Additionally, thermogravimetric analysis revealed that the introduction of GBG fillers significantly improves the thermal stability of the PMMA composites. This work could offer an innovative approach to the design of 222 Rn and gamma radiation shielding materials. Highlights Developed a novel composite for enhanced 222 Rn and gamma radiation shielding. Introduced Gd-based fillers to enhance gamma radiation attenuation in PMMA composites. Achieved superior thermal stability in PMMA composites compared to pure PMMA. Materials designed for application in high-radiation environments, including mining.