Preparation of h‐BN microspheres for nanocomposites with high through‐plane thermal conductivity

In recent times, electronics have been increasingly minimized, and hence, heat dissipation has become essential. Owing to its high thermal conductivity and superior electrical insulation, hexagonal‐boron nitride (h‐BN) has been regarded as an appropriate ceramic material to increase the thermal cond...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 2023-12, Vol.106 (12), p.7240-7250
Main Authors: Mun, Hyung Jin, Park, Ji Young, Lim, Minseob, Cho, Hong‐Baek, Choa, Yong‐Ho
Format: Article
Language:English
Subjects:
Boron nitride
Conductivity
Dissipation
Electrical insulation
Electrical resistivity
Electronics
Heat conductivity
Heat transfer
Isotropy
Microspheres
Nanocomposites
Polydimethylsiloxane
Polymer matrix composites
Polymers
Sintering
Sodium silicates
Thermal conductivity
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Summary:In recent times, electronics have been increasingly minimized, and hence, heat dissipation has become essential. Owing to its high thermal conductivity and superior electrical insulation, hexagonal‐boron nitride (h‐BN) has been regarded as an appropriate ceramic material to increase the thermal conductivity of polymer nanocomposites for effective heat dissipation. However, the poor through‐plane thermal conductivity of h‐BN severely restricts its practical uses, and it is favorable for heat to radiates in the in‐plane direction. In this study, densified spherical h‐BN (sph‐BN) microspheres, composed of as‐synthesized nano‐sized h‐BN (nano‐BN), were manufactured by a spray‐drying process with variations in organic and/or inorganic binders followed by sintering. After incorporating various sph‐BN particles as fillers into polydimethylsiloxane (PDMS), the through‐plane thermal conductivity of composites embedded with sph‐BN, assisted by a sodium silicate binder, enhanced the highest through‐plane and in‐plane thermal conductivities. The composites exhibited high thermal isotropy (through‐plane thermal conductivity/in‐plane thermal conductivity: ) of 0.77. The out‐of‐plane thermal conductivity of the composites was remarkably enhanced by over 2000% compared with pristine PDMS, which can be attributed to the synergy combined with the synthesis of the densified spherical BN initiated by nano‐BN, sintering, and the application of inorganic binders. This study proposes a simple method to prepare polymer composites with h‐BN that exhibit high through‐plane thermal conductivity and are promising materials for heat removal in electronics.
ISSN:0002-7820
1551-2916
DOI:10.1111/jace.19219