Flexible, lightweight, high strength and high efficiently hierarchical Gd2O3/PE composites based on the UHMWPE fibers with self-reinforcing strategy for thermal neutron shielding

To tackle the challenge for materials in the fields such as deep space exploration with flexibility, light weight, high strength, and highly efficient neutron shielding properties, a novel organic-inorganic composites has been developed in this study. Based on ultrahigh molecular weight polyethylene (UHMWPE) fibers self-reinforcing linear low-density polyethylene (LLDPE) matrix method and hierarchical scattering and absorption strategy, a flexibly and light-weight multilayer structure has been designed with alternating gadolinium oxide (Gd2O3)/LLDPE layers and UHMWPE fiber layers by stacking hot-pressing to augment the mechanical properties and neutron shielding efficiency of the composites. Moreover, PE, including UHMWPE fibers and LLDPE matrix, and Gd2O3 has been utilized as neutron shielding element to enhance its neutron scattering and absorption capability via an abundance of hydrogen atoms and Gd element. The neutron shielding performance of the multilayer Gd2O3/UHMWPE/LLDPE composite, with a low density of ca. 1 g/cm3, has been verified by neutron shielding test and a simulation method of equivalent Gd areal density (EGdAD). As a result, an ca. 90.0% neutron shielding efficiency can be achieved with only 2 mm thickness of the composites (with 20 wt.% Gd2O3), and an EGdAD value of 0.0489 g/cm3 is required to achieve 99% shielding efficiency. Moreover, the composites have a significant improvement in the tensile strength and modulus, with an average increase of 1000% (15.86 MPa–179.95 MPa) and 1238% (230.53 MPa–2787.55 MPa) compared to the Gd2O3/LLDPE composites, respectively. The comprehensive performance of our developed multilayer Gd2O3/UHMWPE/LLDPE composites is superior to previously reported results in the literatures. Therefore, it has great application prospect in the various fields like aerospace.