Flexible lead-free gamma-ray radiation shielding using La(OH)3-enhanced natural rubber composites

Ionizing radiation is widely applied in medicine, industry, and agriculture; however, it presents health risks to workers. This study aimed to develop lead-free, flexible gamma-ray shielding composites by incorporating lanthanum hydroxide [La(OH) 3 ] into natural rubber (NR). Composites with varying La(OH) 3 contents (0–250 phr) were prepared using an open two-roll mill and compression molding. Microstructure, mechanical properties, and gamma attenuation were characterized, and the results were compared with XCOM simulations. Gamma shielding was tested at 81–1332 keV using Ba-133, Cs-137, and Co-60 sources. SEM/EDS confirmed uniform La(OH) 3 dispersion in the NR matrix. Density increased from 0.975 g/cm 3 (NR) to 2.156 g/cm 3 (La250/NR), and hardness increased from 27 % to 53 %. Tensile strength decreased from 13.1 MPa to 5.8 MPa, while elongation at break declined from 440 % to 320 %. At 81 keV, the mass attenuation coefficient increased from 0.161 to 2.029 cm 2 /g, and the half-value layer was reduced from 4.41 cm to 0.16 cm (∼96 % reduction). Compared to pure Pb, the HVL ratio of LaOH-natural rubber composite at 81 keV is 5.3, meaning the composite needs about five times greater thickness for equivalent shielding; at 1332 keV, the ratio is 6.04. Experimental results agreed with XCOM within 20 %. The developed LaOH-natural rubber composites demonstrate strong, flexible, and environmentally friendly alternatives for gamma shielding, especially in applications requiring lightweight and wearable protection. • Density increased from 0.975 g/cm 3 to 2.156 g/cm 3 , and hardness rose from 27 shore A to 53 shore A. • Tensile strength decreased from 13.1 MPa to 5.8 MPa, while elongation at break declined to 320 %. • Mass attenuation coefficient increased by over 12 times (from 0.161 to 2.029 cm 2 /g). • The half-value layer (HVL) of La/NR was reduced by ∼96 % (from 4.41 cm to 0.16 cm) at 81 keV. • HVL ratio composite/Pb pure showed values between 9.70 and 5.35 at 81 KeV and 9.92–7.46 at 661 KeV.