Ice‐Templated Assembly Strategy to Construct 3D Boron Nitride Nanosheet Networks in Polymer Composites for Thermal Conductivity Improvement

TLDR

The growing heat‑removal challenge of modern electronics has spurred interest in polymer composites with high thermal conductivity, yet conventional filler addition yields limited conductivity and adverse effects due to high filler loadings. The study reports novel polymer composites by constructing a 3D boron nitride nanosheet network via ice templating and infiltrating it with epoxy. The 3D‑BNNS network is formed using an ice‑templated approach before epoxy infiltration. The resulting composites reach 2.85 W m⁻¹ K⁻¹ thermal conductivity, 24–32 ppm K⁻¹ thermal expansion, and an increased Tg at only 9.29 vol % BNNS loading, demonstrating a promising route for high‑conductivity polymer composites in electronic packaging.

Abstract

Owing to the growing heat removal issue of modern electronic devices, polymer composites with high thermal conductivity have drawn much attention in the past few years. However, a traditional method to enhance the thermal conductivity of the polymers by addition of inorganic fillers usually creates composite with not only limited thermal conductivity but also other detrimental effects due to large amount of fillers required. Here, novel polymer composites are reported by first constructing 3D boron nitride nanosheets (3D‐BNNS) network using ice‐templated approach and then infiltrating them with epoxy matrix. The obtained polymer composites exhibit a high thermal conductivity (2.85 W m −1 K −1 ), a low thermal expansion coefficient (24–32 ppm K −1 ), and an increased glass transition temperature ( T g ) at relatively low BNNSs loading (9.29 vol%). These results demonstrate that this approach opens a new avenue for design and preparation of polymer composites with high thermal conductivity. The polymer composites are potentially useful in advanced electronic packaging techniques, namely, thermal interface materials, underfill materials, molding compounds, and organic substrates.