Fabrication of highly thermally conductive and irradiation resistant UHMWPE-based composites for nuclear shielding applications

Abstract

With the advancement of nuclear energy, the safety of both humans and the surrounding environment necessitates the adoption of effective nuclear radiation shielding materials. Polymer-based shielding materials have garnered attention due to their lightweightness and ease of moldability. However, they normally possess low thermal conductivity (λ) and easy deformation at high temperatures, which potentially cause catastrophic disasters during service if they are mechanically failed due to heat accumulation. To address the above concerns, highly thermally conductive and irradiation resistant ultra-high molecular weight polyethylene (UHMWPE)-based composites were fabricated. Planar fillers such as boron nitride (BN) and graphite (Gt) along with lead (Pb) powders were employed to construct a densely packed filler network for improving the λ and mechanical properties of UHMWPE-based composites. The λ was increased from 3.81 to 6.20 W/mK when 20 wt% Pb (2.88 vol%) was added to BN30/Gt20 (i.e., UHMWPE composite with 30 wt% BN and 20 wt% Gt), representing an increase of 62.73 %. Moreover, the λ of Pb80 was increased from 0.87 to 3.29 W/mK by merely adding 5 wt% (9.99 vol%) Gt, representing a remarkable increase of 278.16 %. GEANT4 simulation results indicated that BN30/Gt20/Pb20 exhibited excellent neutron shielding performance. Samples which were irradiated using 60Co γ-rays at a total dosage of 1.15×105 Gy exhibited enhanced mechanical performance, which indicated excellent irradiation resistance of UHMWPE-based composites. Therefore, a facile method was proposed to prepare multi-functional UHMWPE-based composites that demonstrate promising application in nuclear sectors.