Highly Anisotropic Thermally Conductive Dielectric Polymer/Boron Nitride Nanotube Composites for Directional Heat Dissipation

An ideal dielectric material for microelectronic devices requires a combination of high anisotropic thermal conductivity and low dielectric constant (epsilon ') and loss (tan delta). Polymer composites of boron nitride nanotubes (BNNTs), which offer excellent thermal and dielectric properties, show promise for developing these dielectric polymer composites. Herein, a simple method for fabricating polymer/BNNT composites with high directional thermal conductivity and excellent dielectric properties is presented. The nanocomposites with directionally aligned BNNTs are fabricated through melt-compounding and in situ fibrillation, followed by sintering the fibrous nanocomposites. The fabricated nanocomposites show a significant enhancement in thermal properties, with an in-plane thermal conductivity (K & Vert;) of 1.8 Wm-1K-1-a 450% increase-yielding a high anisotropy ratio (K & Vert;/K perpendicular to) of 36, a 1700% improvement over isotropic samples containing only 7.2 vol% BNNT. These samples exhibit a 120% faster in-plane heat dissipation compared to the through-plane within 2 s. Additionally, they display low epsilon ' of approximate to 3.2 and extremely low tan delta of approximate to 0.014 at 1 kHz. These results indicate that this method provides a new avenue for designing and creating polymer composites with enhanced directional heat dissipation properties along with high K & Vert;, suitable for thermal management applications in electronic packaging, thermal interface materials, and passive cooling systems. Nanocomposites with directionally aligned boron nitride nanotubes (BNNTs) are produced using melt-compounding and in situ fibrillation, followed by sintering. These nanocomposites exhibit a significant improvement in thermal properties, achieving an in-plane thermal conductivity (K & Vert;) of 1.8 Wm-1 K-1, a 450% increase. This results in a high anisotropy ratio (K & Vert;/K perpendicular to) of 36, marking a 1700% enhancement compared to isotropic samples with only 7.2 vol% BNNT. image