Enhanced Thermal Conductivity of Silicone Composites Filled with Few-Layered Hexagonal Boron Nitride

In this study, we demonstrate the use of silicone/few-layered hexagonal boron nitride (FL-hBN) composites for heat dissipation applications. FL-hBN is synthesized via a green, facile, low-cost and scalable liquid exfoliation method using a jet cavitation process. The crystal structures, surface morphologies and specific surface areas of pristine h-BN and FL-hBN were characterized by XRD, SEM, TEM and AFM (atomic force microscopy). The results confirmed that FL-hBN with a thickness of ~4 nm was successfully obtained from the exfoliation process. In addition, we introduced both pristine h-BN and FL-hBN into silicone with different ratios to study their thermal properties. The results of the laser flash analysis indicate that the silicon/FL-hBN composite exhibited a higher thermal conductivity than that of the silicone/h-BN composite. With the optimal loading content of 30 wt.% FL-hBN content, the thermal conductivity of the composite could be enhanced to 230%, which is higher than that of silicone/h-BN (189%). These results indicate that jet cavitation is an effective and swift way to obtain few-layered hexagonal boron nitride that could effectively enhance the thermal conductivity of silicone composites.

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Enhanced thermal conductivity and flame retardancy of polyamide 6/flame retardant composites with hexagonal boron nitride

Journal of Polymer Engineering ◽

10.1515/polyeng-2017-0414 ◽

2018 ◽

Vol 38 (8) ◽

pp. 767-774 ◽

Cited By ~ 4

Author(s):

Liang Wang ◽

Luchong Zhang ◽

Andreas Fischer ◽

Yuhua Zhong ◽

Dietmar Drummer ◽

...

Keyword(s):

Thermal Conductivity ◽

Boron Nitride ◽

Flame Retardant ◽

Flame Retardancy ◽

High Performance ◽

Heat Dissipation ◽

Hexagonal Boron Nitride ◽

Light Emitting Diode ◽

Polyamide 6 ◽

Twin Screw

Abstract High performance composite of polyamide 6 (PA6)/flame retardant (FR)/hexagonal boron nitride (hBN) was prepared via twin screw extrusion, followed by injection molding. The heat dissipation of the composite was significantly improved by incorporating 40 vol% of hBN, and the corresponding thermal conductivity was up to 5.701 W/(m·K), nearly 17 times that of the PA6/FR composites. In addition, the combination effect of hBN and FR to the flame retardancy of the composites was observed, and the addition of hBN could dramatically enhance the flame retardancy of composites, achieving a UL94 V-0 rating with a limited oxygen index (LOI) value of 37%. This multifunctional modification would broaden the application field of PA6 composites in light-emitting diode (LED) lamps, electronic products, and so on.

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Heat Dissipation in Epoxy/Amine-Based Gradient Composites with Alumina Particles: A Critical Evaluation of Thermal Conductivity Measurements

Polymers ◽

10.3390/polym10101131 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1131 ◽

Cited By ~ 7

Author(s):

Matthias Morak ◽

Philipp Marx ◽

Mario Gschwandl ◽

Peter Filipp Fuchs ◽

Martin Pfost ◽

...

Keyword(s):

Thermal Conductivity ◽

Heat Dissipation ◽

Critical Evaluation ◽

Laser Flash ◽

Element Analysis ◽

Epoxy Amine ◽

Alumina Particles ◽

Laser Flash Analysis ◽

Key Aspects ◽

Guarded Heat Flow Meter

Abstract: For the design of the next generation of microelectronic packages, thermal management is one of the key aspects and must be met by the development of polymers with enhanced thermal conductivity. While all polymer classes show a very low thermal conductivity, this shortcoming can be compensated for by the addition of fillers, yielding polymer-based composite materials with high thermal conductivity. The inorganic fillers, however, are often available only in submicron- and micron-scaled dimensions and, consequently, can sediment during the curing reaction of the polymer matrix. In this study, an epoxy/amine resin was filled with nano- and submicron-scaled alumina particles, yielding a gradient composite. It was found that the thermal conductivity according to laser flash analysis of a sliced specimen ranged from 0.25 to 0.45 W·m−1·K−1 at room temperature. If the thermal conductivity of an uncut specimen was measured with a guarded heat flow meter, the ‘averaged’ thermal conductivity was measured to be only 0.25 W·m−1·K−1. Finite element analysis revealed that the heat dissipation through a gradient composite was of intermediate speed in comparison with homogeneous composites exhibiting a non-gradient thermal conductivity of 0.25 and 0.45 W·m−1·K−1.

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High thermal conductivity of high-quality monolayer boron nitride and its thermal expansion

Science Advances ◽

10.1126/sciadv.aav0129 ◽

2019 ◽

Vol 5 (6) ◽

pp. eaav0129 ◽

Cited By ~ 50

Author(s):

Qiran Cai ◽

Declan Scullion ◽

Wei Gan ◽

Alexey Falin ◽

Shunying Zhang ◽

...

Keyword(s):

Thermal Conductivity ◽

Thermal Expansion ◽

Boron Nitride ◽

Density Functional ◽

Heat Dissipation ◽

Hexagonal Boron Nitride ◽

High Thermal Conductivity ◽

Unit Weight ◽

High Quality ◽

Dynamic Simulations

Heat management has become more and more critical, especially in miniaturized modern devices, so the exploration of highly thermally conductive materials with electrical insulation is of great importance. Here, we report that high-quality one-atom-thin hexagonal boron nitride (BN) has a thermal conductivity (κ) of 751 W/mK at room temperature, the second largest κ per unit weight among all semiconductors and insulators. The κ of atomically thin BN decreases with increased thickness. Our molecular dynamic simulations accurately reproduce this trend, and the density functional theory (DFT) calculations reveal the main scattering mechanism. The thermal expansion coefficients of monolayer to trilayer BN at 300 to 400 K are also experimentally measured for the first time. Owing to its wide bandgap, high thermal conductivity, outstanding strength, good flexibility, and excellent thermal and chemical stability, atomically thin BN is a strong candidate for heat dissipation applications, especially in the next generation of flexible electronic devices.

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Thermal and dielectric properties of epoxy-based composites filled with flake and whisker type hexagonal boron nitride materials

High Performance Polymers ◽

10.1177/0954008320959413 ◽

2020 ◽

pp. 095400832095941

Author(s):

Rongkun Yang ◽

Mingming Sheng ◽

Yujun Zhang ◽

Hongyu Gong ◽

Xiao Lin ◽

...

Keyword(s):

Thermal Conductivity ◽

Dielectric Properties ◽

Boron Nitride ◽

Epoxy Resin ◽

Heat Dissipation ◽

Hexagonal Boron Nitride ◽

Transmission Efficiency ◽

Pure Epoxy ◽

The Matrix ◽

Properties Of Composites

In this work, the epoxy-based composites filled with 3-Aminopropyltriethoxysilane (KH-550) modified binary filler of hexagonal boron nitride (h-BN) flakes and h-BN whiskers were fabricated, and the thermal and dielectric properties of composites were systematically investigated. Adding h-BN whiskers to the filler could effectively form heat conduction paths and improve the phonon transmission efficiency, thereby improving the thermal conductivity of the composites. According to our results, the thermal conductivity of composite with 27 wt% h-BN flakes and 3 wt% h-BN whiskers reached up to 0.819 W·m−1·K−1, which was 3.9 times that of pure epoxy resin. At the same time, the dielectric loss value and dielectric constant of this composite at 1 MHz were 0.02678 and 4.55, respectively, while pure epoxy resin were 0.03602 and 4.33. In addition, introducing h-BN whiskers into the matrix could effectively improve the thermal stability and heat dissipation performance of composites.

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Effects of Anodizing Conditions on Thermal Properties of Al 20XX Alloys for Aircraft

Symmetry ◽

10.3390/sym13030433 ◽

2021 ◽

Vol 13 (3) ◽

pp. 433

Author(s):

Junghyun Park ◽

Kyeongsik Son ◽

Junghoon Lee ◽

Donghyun Kim ◽

Wonsub Chung

Keyword(s):

Sulfuric Acid ◽

Heat Dissipation ◽

Digital Camera ◽

High Hardness ◽

Laser Flash ◽

Mixed Acid ◽

Aerospace Applications ◽

Laser Flash Analysis ◽

Ft Ir ◽

Optimized Conditions

Anodizing was applied to improve the heat dissipation performance of aluminum (Al) alloys, by forming an oxide layer, such that they could be employed in aerospace applications. The methods employed were hard sulfuric acid (high hardness), soft sulfuric acid (low hardness), boric-sulfuric mixed acid, tin-sulfuric mixed acid, and chromic acid solutions. Each process was completed under optimized conditions. The surface morphology was observed using field emission scanning electron microscopy (FE-SEM) and a digital camera. For the determination of thermal performance, Fourier transform infrared spectroscopy (FT-IR) was used to measure the emissivity at 50 °C, and laser flash analysis (LFA) was utilized to analyze the thermal diffusivity at room temperature to 300 °C. The radiative property of metals is often ignored because of their low emissivity, however, in this research, the emissivity of the metal oxides was found to be higher than that of bare metal series. This study improved the heat dissipation properties by oxidization of Al via the anodizing process.

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