Investigating optimal region for thermal and electrical properties of epoxy nanocomposites under high frequencies and temperatures

Abstract This research investigates the optimal region to achieve balanced thermal and electrical insulation properties of epoxy (EP) under high frequency (HF) and high temperature (HT) via integration of surface-modified hexagonal boron nitride (h-BN) nanoparticles. The effects of nanoparticle content and high temperature on various electrical (DC, AC, and high frequency) and thermal properties of EP are investigated. It is found that the nano h-BN addition enhances thermal performance and weakens electrical insulation properties. On the other side, under HF and HT stress, the presence of h-BN nanoparticles significantly improves the electrical performance of BN/EP nanocomposites. The EP has superior insulation properties at low temperature and low frequency, whereas the BN/EP nanocomposites exhibit better insulation performance than EP under HF and HT. The factors such as homogeneous nanoparticle dispersion in EP, enhanced thermal conductivity, nanoparticle surface modification, weight percent of nanoparticles, the mismatch between the relative permittivity of EP and nano h-BN, and the presence of voids in nanocomposites play the crucial role. The optimal nanoparticle content and homogenous dispersion can produce suitable EP composites for the high frequency and high temperature environment, particularly solid-state transformer applications.

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Improved Thermal Conductivities of Epoxy Resins Containing Surface Functionalized BN Nanosheets

NANO ◽

10.1142/s1793292018501333 ◽

2018 ◽

Vol 13 (11) ◽

pp. 1850133 ◽

Cited By ~ 1

Author(s):

Ling Weng ◽

HeBing Wang ◽

Xiaorui Zhang ◽

Lizhu Liu ◽

Hexin Zhang

Keyword(s):

Thermal Conductivity ◽

Epoxy Resins ◽

Hexagonal Boron Nitride ◽

Electrical Insulation ◽

Coupling Agents ◽

Thermal And Mechanical Properties ◽

Silane Coupling Agents ◽

Silane Coupling ◽

Ep Matrix ◽

Electrical Insulation Properties

The hexagonal boron nitride nanosheets (BN) were firstly treated by silane coupling agents 3-aminopropyltriethoxysilane (KH550) and 3-glycidoxypropyl-trimethoxysilane (KH560) to introduce some amino and epoxy (EP) groups on the BN surface. These modified BN nanosheets were incorporated into an EP matrix to prepare BN@KH560/EP composites with excellent thermal conductivity and electrical insulation properties. Results showed that the thermal conductivity of BN@KH560/EP composite with 20[Formula: see text]vol% BN dosage was found to be 0.442[Formula: see text]W/(m[Formula: see text]K), which was 81% higher than that of pure EP resin. Both BN/EP composites treated by KH550 and KH560 showed rather good electrical insulation properties, although the dielectric constant of BN@KH550/EP composites were slightly higher than BN@KH560/EP composites. Moreover, BN@KH560/EP composites also showed better thermal and mechanical properties than that of BN@KH550/EP composites.

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Aerogel Perfusion-Prepared h-BN/CNF Composite Film with Multiple Thermally Conductive Pathways and High Thermal Conductivity

Nanomaterials ◽

10.3390/nano9071051 ◽

2019 ◽

Vol 9 (7) ◽

pp. 1051 ◽

Cited By ~ 12

Author(s):

Xiu Wang ◽

Zhihuai Yu ◽

Liang Jiao ◽

Huiyang Bian ◽

Weisheng Yang ◽

...

Keyword(s):

Thermal Conductivity ◽

Composite Film ◽

Hexagonal Boron Nitride ◽

Traditional Approach ◽

Synthetic Polymer ◽

Electrical Insulation ◽

High Thermal Conductivity ◽

Polymer Materials ◽

Thermally Conductive ◽

Electrical Insulation Properties

Hexagonal boron nitride (h-BN)-based heat-spreading materials have drawn considerable attention in electronic diaphragm and packaging fields because of their high thermal conductivity and desired electrical insulation properties. However, the traditional approach to fabricate thermally conductive composites usually suffers from low thermal conductivity, and cannot meet the requirement of thermal management. In this work, novel h-BN/cellulose-nano fiber (CNF) composite films with excellent thermal conductivity in through plane and electrical insulation properties are fabricated via an innovative process, i.e., the perfusion of h-BN into porous three dimensional (3D) CNF aerogel skeleton to form the h-BN thermally conductive pathways by filling the CNF aerogel voids. When at an h-BN loading of 9.51 vol %, the thermal conductivity of h-BN/CNF aerogel perfusion composite film is 1.488 W·m−1·K−1 at through plane, an increase by 260.3%. The volume resistivity is 3.83 × 1014 Ω·cm, superior to that of synthetic polymer materials (about 109~1013 Ω·cm). Therefore, the resulting h-BN/CNF film is very promising to replace the traditional synthetic polymer materials for a broad spectrum of applications, including the field of electronics.

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