Fabricating UHMWPE‐based shielding materials with excellent high‐temperature mechanical properties and irradiation endurance properties via controlling crosslinked and crystalline structures

Abstract

Shielding materials are important guarantees for the reliable operation of nuclear equipment and essential prerequisites for the safe application of nuclear energy. As an essential and most widely used shielding material, improving the high‐temperature mechanical properties of PE‐based shielding material is of significant importance for the lightweight and integrated design of nuclear shielding material systems. Here, a simple crosslinking method was proposed to control the crosslinking degree and crystallinity to prepare UHMWPE‐based shielding materials with excellent high‐temperature mechanical properties and irradiation endurance properties. The enhancement mechanisms of mechanical properties, irradiation endurance properties and shielding properties were revealed. Meanwhile, the γ‐rays and neutrons shielding properties were studied using Geant4. When the crosslinking degree was 20.62 × 10−3 g/mol and the crystallinity was 12.13%, UHMPE‐based shielding material with optimal overall performance was obtained. Compared with the un‐crosslinked control sample, the tensile strength and elongation at break at room temperature, 70 and 90°C were 22.3 MPa (48.90% increased) and 8.43% (154.68% increased), 8.65 MPa (105.46% increased) and 6.35% (154.00% increased), 7.48 MPa (128.75% increased) and 6.2% (89.60% increased), respectively. The vicat softening temperature and maximum thermal deformation temperature were enhance 4.20 and 6.56°C when the crosslinking degree was 27.51 × 10−3 g/mol and the crystallinity is 10.83%. Our work provided a feasible method to increase the upper temperature limit and broaden the application range of PE‐based nuclear shielding materials.

Fabrication of Thermally Conductive and Wear-Resistant UHMWPE-Based Composites for Nuclear Shielding Applications

“…Thus, light atoms such as H-containing materials can shield fast neutrons due to their neutron moderation capabilities because light atoms slow down the speed of neutrons through elastic scattering . PE, which is composed of C and H atoms, is a primarily used matrix for neutron shielding in nuclear sectors. , Generally, a larger neutron capture cross-section indicates a higher neutron capture capability and contributes more to shielding fast neutrons. , Boron (B) possesses a high absorption cross-section for neutrons, thereby enabling effective neutron absorption to control and mitigate neutron radiation . Materials containing B element, such as BN and boron carbide (B 4 C), are added to PE, polyester, and epoxy to fabricate radiation-shielding composites. − …”