Adel Fisli, Asron Ferdian Falaah, Deni Mustika, Sulistioso Giat Sukaryo, Sairun, Nadya Nurdini, Saeful Yusuf, Th. Rina Mulyaningsih, Agus Salim Afrozi, Auring Rachminisari, Agus Taufiq, Agus Sunardi, Syukri Arief, Henry Prastanto, Mohamad Irfan Fathurrohman, Ridwan
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.