Neutron and gamma radiation shielding properties of transparent polymethyl methacrylate copolymers containing gadolinium

In this study, transparent polymethyl methacrylate (PMMA) copolymers containing gadolinium (Gd) were prepared through copolymerization of gadolinium methacrylate [Gd(MAA)3] and methyl methacrylate. The neutron and gamma-ray shielding properties of the copolymers were evaluated using a 252Cf neutron source and a 241Am gamma source. The shielding performance of the copolymers against moderated 252Cf neutrons (12-cm-thick polyethylene was used as the moderator) improved with increasing Gd(MAA)3 content. However, when the Gd(MAA)3 content exceeded 10%, the enhancement in neutron shielding was negligible. The macroscopic thermal neutron absorption cross section of the copolymer containing 10% Gd(MAA)3 was 0.79 cm−1. The copolymers’ shielding against gamma rays improved with increasing Gd(MAA)3 content, and a linear attenuation coefficient was 2.10 cm−1 for the copolymer containing 30% Gd(MAA)3. The incorporation of Gd into PMMA effectively enhanced the material’s ability to shield against both thermal neutrons and gamma rays and did not negatively affect its visible-light transmittance. In addition, as the content of Gd(MAA)3 increased, the thermal stability of gadolinium-containing PMMA increased, while its tensile strength decreased. The copolymers with 30% Gd(MAA)3 retained approximately 67% residue at 500 °C, whereas its tensile strength dropped from 67 to 9 MPa. These findings provide valuable insights for the development of transparent equipment for protection against neutron and gamma radiation.