Synthesis of size-controlled and in-situ OH functionalized hexagonal boron nitride powder by hetero-phase reaction

Song, Yoseb; Kim, Seil; Lim, Minseob; Cho, Hong‐Baek; Choa, Yong‐Ho

doi:10.1016/j.apsusc.2021.149885

Cited by 7 publications

(4 citation statements)

References 11 publications

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“…Figure shows the schematic for the preparation of nano-BN, sph-nano-BN, and xmicro-BN/sph-nano-BN/PDMS composites. In brief, the synthetic reaction for nano-BN occurs in a so-called heterophase liquid–vapor interfacial reaction, as reported in our previous work . During the process, melamine, which has a relatively low melting point compared to that of boron trioxide, sublimes first in the crucible at temperatures ranging from 340 to 350 °C, and then the boron trioxide starts melting at temperatures above 450 °C.…”

Section: Resultsmentioning

confidence: 95%

“…In brief, the synthetic reaction for nano-BN occurs in a so-called heterophase liquid−vapor interfacial reaction, as reported in our previous work. 31 During the process, melamine, which has a relatively low melting point compared to that of boron trioxide, sublimes first in the crucible at temperatures ranging from 340 to 350 °C, and then the boron trioxide starts melting at temperatures above 450 °C. The synthetic reaction site is the interface between molten boron trioxide liquid and sublimed melamine vapor phases.…”

Section: Preparation and Characterization Of Nano-bn And Sph-nano-bnmentioning

confidence: 99%

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High Quasi-Isotropic Thermal Conductivity of Polydimethylsiloxane Nanocomposites with Hexagonal-Boron Nitride Microspheres and Flakes

Mun,

Cho,

Choa

2024

ACS Appl. Polym. Mater.

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Boron nitride has been widely utilized as a filler to increase the thermal conductivity of polymers due to its unique features, such as electrical insulation, high thermal conductivity, high breakdown strength, and physical and chemical stability. However, the two-dimensional hexagonal-boron nitride (h-BN) has an anisotropic structure, showing a tendency to align horizontally under external pressure, resulting in a limited increase of through-plane thermal conductivity for polymer composites.To address this, we conducted a study where we synthesized h-BN microspheres (sph-nano-BN) using a spray-drying technique from nanosized h-BN (nano-BN). These microspheres, along with a combination of microsized h-BN flakes, are incorporated into polydimethylsiloxane (PDMS) to improve the quasi-isotropic thermal conductivity of the composites. The resulting composites, which contained both large lateral h-BN flakes and sph-nano-BN, exhibited the highest through-plane thermal conductivity of over 6 W/mK, which increased by 3000% compared to that of pure PDMS, thanks to the prevention of the in-plane arrangement of h-BN flakes by sph-nano-BN particles. Additionally, the composites showed a high thermal isotropy (through-plane thermal conductivity/ in-plane thermal conductivity: λ ⊥ /λ // ) of 0.75, representing an increase of over 1.5 times compared to that of previous literature. This study presents a simple yet straightforward approach to enhance quasi-isotropic thermal conductivity in polymer composites, making it immediately applicable to the future design of composites for heat removal in versatile electronics.

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Section: Resultsmentioning

confidence: 95%

Section: Preparation and Characterization Of Nano-bn And Sph-nano-bnmentioning

confidence: 99%

High Quasi-Isotropic Thermal Conductivity of Polydimethylsiloxane Nanocomposites with Hexagonal-Boron Nitride Microspheres and Flakes

Mun,

Cho,

Choa

2024

ACS Appl. Polym. Mater.

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“…The nano-BN used in this work was synthesized from our previous study. 46 Triton X-102 and PVP (∼MW 55 000) were purchased from Sigma Aldrich Co., Ltd., USA. Sodium silicate solution including 28.0%-38.0% silicon dioxide and 9.0%-19.0% sodium dioxide in water was provided by Duksan Co., Korea.…”

Section: Methodsmentioning

confidence: 99%

“…PDMS (SYLGARD 184) prepolymer and its curing agent were supplied by Dow Corning Co., USA. The nano‐BN used in this work was synthesized from our previous study 46 . Triton X‐102 and PVP (∼MW 55 000) were purchased from Sigma Aldrich Co., Ltd., USA.…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2023

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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.

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Exfoliation methods and functionalization techniques of hexagonal boron nitride

Bhavya,

Surendran

2024

Hexagonal Boron Nitride

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Synthesis of size-controlled and in-situ OH functionalized hexagonal boron nitride powder by hetero-phase reaction

Cited by 7 publications

References 11 publications

High Quasi-Isotropic Thermal Conductivity of Polydimethylsiloxane Nanocomposites with Hexagonal-Boron Nitride Microspheres and Flakes

High Quasi-Isotropic Thermal Conductivity of Polydimethylsiloxane Nanocomposites with Hexagonal-Boron Nitride Microspheres and Flakes

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

Exfoliation methods and functionalization techniques of hexagonal boron nitride

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