Highly thermally conductive and mechanically robust composite of linear ultrahigh molecular weight polyethylene and boron nitride via constructing nacre-like structure

With the rapid development of modern electronic, developing highly thermally conductive and mechanically strong composites for achieving efficient and reliable thermal management has become an urgent task. In this work, boron nitride/linear-ultrahigh molecular weight polyethylene (LUHMWPE) composites with strong mechanical performance and high thermal conductivity (23.03 W/(mK) were fabricated by solid-state extrusion (SSE) method. The thermal conductivity achieved in this work is the highest for bulk polymer so far. The effects of extrusion draw ratio (EDR) on the morphology, structure, and thermal properties were also investigated. With increase in EDR, the original isotropic structure gradually transforms into nacre-like structure due to the extensive elongational flow field during SSE, accompanied by the augment of thermal conduction performance and mechanical properties. We attribute the high thermal conductivity and mechanical properties to the construction of nacre-like structure, where the h-BN platelets and LUHMWPE molecular chains are highly oriented. Our bioinspired composites have potential applications in thermal management field for modern electronics.