Advanced polyurethane/boron nitride nanotube composites for thermal management and neutron shielding

Boron nitride nanotubes (BNNTs) have attracted significant attention as advanced nanomaterials because of their unique combination of exceptional thermal conductivity, mechanical strength, and electrical insulation properties. However, challenges in achieving high dispersion and compatibility with polymer matrices have limited their practical applications. In this study, we present a new strategy to synthesize high-performance polyurethane foam (PUF) composites integrated with BNNTs. The polyurethane matrix was chemically modified using phenylboronic acid (PBA), enabling strong interfacial interactions with BNNTs and enhancing their dispersion. BNNTs were incorporated in situ during polymerization to produce PUF/BNNT composites, and the composite was further densified via melt blending and hot-pressing to achieve a high BNNT loading. Comprehensive evaluations revealed significant improvements in mechanical strength, thermal conductivity, and neutron shielding performance, positioning these composites as next-generation materials for demanding applications such as thermal management and radiation shielding. This work represents a breakthrough in the scalable fabrication of multifunctional BNNT-based polymer composites.