scholarly journals Temperature Effects on the Dielectric Properties and Breakdown Performance of h-BN/Epoxy Composites

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4112 ◽  
Author(s):  
Yongzhe Tang ◽  
Peng Zhang ◽  
Mingxiao Zhu ◽  
Jiacai Li ◽  
Yuxia Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Dielectric Constant ◽  
Boron Nitride ◽  
Mass Fraction ◽  
Breakdown Strength ◽  
Hexagonal Boron Nitride ◽  
Glassy State ◽  
Internal Heat ◽  
Heat Accumulation ◽  
Different Temperatures

Epoxy–boron nitride composites are promising insulating materials, and it is highly important to understand their insulating performances at different temperatures with different nano-doping amounts. In this study, we investigated the effects of different mass fractions of epoxy–micron hexagonal boron nitride composites on their thermal conductivity, as well as the effects of temperature and mass fraction on their insulating performances. The results demonstrated that the thermal conductivity of epoxy–micron hexagonal boron nitride composites was superior to that of neat epoxy. The thermal conductivity of epoxy–micron hexagonal boron nitride composites increased with the mass fraction of hexagonal boron nitride, and their dielectric constant and dielectric loss increased with temperature. The dielectric constant of epoxy–micron hexagonal boron nitride composites decreased as the mass fraction of hexagonal boron nitride increased, while their dielectric losses decreased and then increased as the mass fraction of hexagonal boron nitride increased. Due to internal heat accumulation, the alternating current breakdown strength of epoxy–micron hexagonal boron nitride composites increased and then decreased as the mass fraction of hexagonal boron nitride increased. Additionally, as the temperature increased, the composites transitioned from the glassy state to the rubbery or viscous state, and the breakdown strength significantly degraded.

scholarly journals Controllable Thermal Conductivity in Twisted Homogeneous Interfaces of Graphene and Hexagonal Boron Nitride

Nano Letters ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 7513-7518
Author(s):  
Wengen Ouyang ◽  
Huasong Qin ◽  
Michael Urbakh ◽  
Oded Hod
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride

scholarly journals Recent Progress in the Study of Thermal Properties and Tribological Behaviors of Hexagonal Boron Nitride-Reinforced Composites

2020 ◽  
Vol 4 (3) ◽  
pp. 116
Author(s):  
Maryam Khalaj ◽  
Sanaz Zarabi Golkhatmi ◽  
Sayed Ali Ahmad Alem ◽  
Kahila Baghchesaraee ◽  
Mahdi Hasanzadeh Azar ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Recent Progress ◽  
Phonon Scattering ◽  
Hexagonal Boron Nitride ◽  
High Thermal Conductivity ◽  
Promising Candidate ◽  
Reinforced Composite ◽  
Low Thermal Expansion ◽  
Wide Range

Ever-increasing significance of composite materials with high thermal conductivity, low thermal expansion coefficient and high optical bandgap over the last decade, have proved their indispensable roles in a wide range of applications. Hexagonal boron nitride (h-BN), a layered material having a high thermal conductivity along the planes and the band gap of 5.9 eV, has always been a promising candidate to provide superior heat transfer with minimal phonon scattering through the system. Hence, extensive researches have been devoted to improving the thermal conductivity of different matrices by using h-BN fillers. Apart from that, lubrication property of h-BN has also been extensively researched, demonstrating the effectivity of this layered structure in reduction of friction coefficient, increasing wear resistance and cost-effectivity of the process. Herein, an in-depth discussion of thermal and tribological properties of the reinforced composite by h-BN will be provided, focusing on the recent progress and future trends.

scholarly journals Preparation of Boron Nitride Nanoplatelets via Amino Acid Assisted Ball Milling: Towards Thermal Conductivity Application

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1652
Author(s):  
Nan Yang ◽  
Haifeng Ji ◽  
Xiaoxia Jiang ◽  
Xiongwei Qu ◽  
Xiaojie Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Amino Acid ◽  
Boron Nitride ◽  
Ball Milling ◽  
Hexagonal Boron Nitride ◽  
Base Material ◽  
Single Layer ◽  
Self Healing ◽  
Dispersion State ◽  
Pva Hydrogel

Hexagonal boron nitride nanoplatelets (BNNPs) have attracted widespread attention due to their unique physical properties and their peeling from the base material. Mechanical exfoliation is a simple, scalable approach to produce single-layer or few-layer BNNPs. In this work, two amino acid grafted boron nitride nanoplatelets, Lys@BNNP and Glu@BNNP, were successfully prepared via ball milling of h-BN with L-Lysine and L-Glutamic acid, respectively. It was found that the dispersion state of Lys@BNNP and Glu@BNNP in water had been effectively stabilized due to the introduction of amino acid moieties which contained a hydrophilic carboxyl group. PVA hydrogel composites with Lys@BNNP and Glu@BNNP as functional fillers were constructed and extensively studied. With 11.3 wt% Lys@BNNP incorporated, the thermal conductivity of Lys@BNNP/PVA hydrogel composite was up to 0.91 W m−1K−1, increased by 78%, comparing to the neat PVA hydrogel. Meanwhile, the mechanical and self-healing properties of the composites were simultaneously largely enhanced.

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