3D Multilayered BNMR/Epoxy Composites with Enhanced Neutron Shielding Performance for Protection of Space Electronics.

With the rapid advancement of space technologies, ensuring the reliable performance of electronic systems in extreme space environments has become increasingly critical. However, conventional polymeric materials used in electronic device packaging suffer from insufficient neutron shielding capability and poor thermal stability, requiring improved effectiveness in protecting sensitive components from high-energy radiation and drastic temperature fluctuations. In this study, we report a novel multilayered composite consisting of boron nitride microbridle (BNMR) and epoxy resin. Conventional BN materials can provide effective intrinsic neutron shielding capability, with minimal generation of secondary radiation, but often face limitations in cost and applicability. The BNMR, synthesized via a cost-effective method, was aligned into dense-layered structures using freeze-casting and subsequently infiltrated with epoxy. This architecture promotes uniform filler distribution, enhanced interfacial bonding, and multiple neutron scattering, which collectively lead to significant improvement in shielding performance. The composite achieved a 226.53% increase in neutron attenuation coefficient with only 5.35 vol % BNMR, compared to pure epoxy. Additionally, the composite exhibited reduced thermal expansion and improved electrical insulation over a wide temperature range (-100-100 °C), demonstrating its applicability under extreme space conditions. These results suggest that the BNMR/epoxy multilayer composite is a promising candidate for advanced electronic packaging materials in aerospace environments.