Epoxy Composites Filled With Hydrothermally Synthesized (BiO)4CO3(OH)2@Gd2O(CO3)2·H2O Exhibiting Enhanced Gamma Ray Shielding Performance and Thermal Stability

The development of efficient gamma-ray shielding materials is crucial for addressing increasingly complex radiation environments. In this study, (BiO) 4 CO 3 (OH) 2 (BCH) and (BiO) 4 CO 3 (OH) 2 @Gd 2 O(CO 3 ) 2 ·H 2 O (BG) fillers were synthesized via a hydrothermal method. After being dispersed into epoxy resin by mechanical stirring, the mixtures were molded using a vacuum-assisted thermal curing process. Under 59.5 keV gamma irradiation, the linear attenuation coefficient (LAC) of BG/EP-50 reached 5.8 cm −1 , representing an 84% increase compared to BCH/EP-50 (3.15 cm −1 ) and about 33 times that of pure EP (0.17 cm −1 ). In addition, the temperature at 50% weight loss (T 50% ) of BG/EP-50 increased to 637.9〬C, which is 60.9% higher than that of the epoxy matrix, indicating improved thermal stability. The BG filler, constructed through a simple two-step hydrothermal route, demonstrated a synergistic effect between Bi and Gd components, which not only compensated for the limitations of Bi in the low-energy region but also enhanced the gamma shielding capability of the epoxy resin at higher energies. Compared to several shielding materials reported in recent years, BG/EP-50 shows superior performance and offers a promising strategy for lightweight and environmentally friendly polymer-based gamma shielding materials.