Thermal Conductivity Enhancement of Polymeric Composites Using Hexagonal Boron Nitride: Design Strategies and Challenges

Abstract

With the integration and miniaturization of chips, there is an increasing demand for improved heat dissipation. However, the low thermal conductivity (TC) of polymers, which are commonly used in chip packaging, has seriously limited the development of chips. To address this limitation, researchers have recently shown considerable interest in incorporating high-TC fillers into polymers to fabricate thermally conductive composites. Hexagonal boron nitride (h-BN) has emerged as a promising filler candidate due to its high-TC and excellent electrical insulation. This review comprehensively outlines the design strategies for using h-BN as a high-TC filler and covers intrinsic TC and morphology effects, functionalization methods, and the construction of three-dimensional (3D) thermal conduction networks. Additionally, it introduces some experimental TC measurement techniques of composites and theoretical computational simulations for composite design. Finally, the review summarizes some effective strategies and possible challenges for the design of h-BN fillers. This review provides researchers in the field of thermally conductive polymeric composites with a comprehensive understanding of thermal conduction and constructive guidance on h-BN design.

Methods for Preparation of Hexagonal Boron Nitride Nanomaterials

“…A monolayer of high-quality h -BN nanosheet showcases an in-plane thermal conductivity of 751 W/(m·K), second only to diamond among all semiconductors and insulators . The exceptional thermal property of h -BN, coupled with its electrical insulation characteristics, allows for its integration as a filler into polymers and results in composite materials that are thermally conductive yet electrically insulating, making h -BN an exceedingly attractive choice for thermal management applications in electronic devices …”

“…Furthermore, the strong covalent bonds between B and N atoms provide a high interatomic binding energy, allowing thermal energy to be transmitted through the lattice vibrations (phonons) with high efficiency. The unique layered structure minimizes phonon scattering caused by disordered lattices within the h -BN, leading to a high thermal conductivity (TC) range from 200 to 2000 W/(m·K). ,, In particular, the TC of h -BN is intricately linked to its nanostructure morphology. For instance, at room temperature, the TC of BNNTs with an outer diameter of 32 nm reaches approximately 350 W/(m·K), which surpasses that of carbon nanotubes of similar diameters .…”