scholarly journals Optimization of Boron Nitride Sphere Loading in Epoxy: Enhanced Thermal Conductivity and Excellent Electrical Insulation

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1335 ◽  
Author(s):  
Hua Zhang ◽  
Rongjin Huang ◽  
Yong Li ◽  
Hongbo Li ◽  
Zhixiong Wu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Dielectric Material ◽  
Coefficient Of Thermal Expansion ◽  
Superconducting Magnet ◽  
New Approach ◽  
Spherical Structure ◽  
Wide Range ◽  
Thermally Conductive ◽  
Traditional Approaches

Thermally conductive but electrically insulating materials are highly desirable for thermal management applications in electrical encapsulation and future energy fields, for instance, superconducting magnet insulation in nuclear fusion systems. However, the traditional approaches usually suffer from inefficient and anisotropic enhancement of thermal conductivity or deterioration of electrical insulating property. In this study, using boron nitride sphere (BNS) agglomerated by boron nitride (BN) sheets as fillers, we fabricate a series of epoxy/BNS composites by a new approach, namely gravity-mix, and realize the controllable BNS loading fractions in the wide range of 5–40 wt%. The composites exhibited thermal conductivity of about 765% and enhancement at BNS loading of 40 wt%. The thermal conductivity up to 0.84 W·m−1·K−1 at 77 K and 1.66 W·m−1·K−1 at 298 K was observed in preservation of a higher dielectric constant and a lower dielectric loss, as expected, because boron nitride is a naturally dielectric material. It is worth noting that the thermal property was almost isotropous on account of the spherical structure of BNS in epoxy. Meanwhile, the reduction of the coefficient of thermal expansion (CTE) was largely reduced, by up to 42.5% at a temperature range of 77–298 K.

scholarly journals Surface modification of a BN/ETDS composite with aniline trimer for high thermal conductivity and excellent mechanical properties

RSC Advances ◽  
2018 ◽  
Vol 8 (40) ◽  
pp. 22846-22852 ◽  
Author(s):  
Seokgyu Ryu ◽  
Taeseob Oh ◽  
Jooheon Kim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Surface Modification ◽  
Boron Nitride ◽  
Polymer Composites ◽  
Conductive Polymer ◽  
High Thermal Conductivity ◽  
Conductive Polymer Composites ◽  
Thermally Conductive

Boron nitride (BN) particles surface-treated with different amounts of aniline trimer (AT) were used to prepare thermally conductive polymer composites with epoxy-terminated dimethylsiloxane (ETDS).

Adaptive Thermal Conductivity Metamaterials: Enabling Active and Passive Thermal Control

2018 ◽  
Vol 10 (5) ◽  
Author(s):  
Austin A. Phoenix ◽  
Evan Wilson
Keyword(s):  
Thermal Conductivity ◽  
Thermal Management ◽  
Passive Control ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Strain ◽  
Thermal Control ◽  
Variable Thermal Conductivity ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Nonlinear Thermal Conductivity

The novel adaptive thermal metamaterial developed in this paper provides a unique thermal management capability that can address the needs of future spacecraft. While advances in metamaterials have provided the ability to generate materials with a broad range of material properties, relatively little advancement has been made in the development of adaptive metamaterials. This metamaterial concept enables the development of materials with a highly nonlinear thermal conductivity as a function of temperature. Through enabling active or passive control of the metamaterials bulk effective thermal conductivity, this metamaterial that can improve the spacecraft's thermal management systems performance. This variable thermal conductivity is achieved through induced contact that results in changes in the F path length and the conductive path area. The contact can be generated internally using thermal strain from shape memory alloys, bimetal springs, and mismatches in coefficient of thermal expansion (CTE) or it can be generated externally using applied mechanical loading. The metamaterial can actively control the temperature of an interface by dynamically changing the bulk thermal conductivity controlling the instantaneous heat flux through the metamaterial. The design of thermal stability regions (regions of constant thermal conductivity versus temperature) into the nonlinear thermal conductivity as a function of temperature can provide passive thermal control. While this concept can be used in a wide range of applications, this paper focuses on the development of a metamaterial that achieves highly nonlinear thermal conductivity as a function of temperature to enable passive thermal control of spacecraft systems on orbit.

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.

Antimicrobial hexagonal boron nitride nanoplatelet composites for the thermal management of medical electronic devices

2019 ◽  
Vol 3 (11) ◽  
pp. 2455-2462 ◽  
Author(s):  
Si-Wei Xiong ◽  
Pan Zhang ◽  
Yu Xia ◽  
Pei-Gen Fu ◽  
Jing-Gang Gai
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Thermal Management ◽  
Hexagonal Boron Nitride ◽  
Electronic Devices ◽  
E Coli ◽  
Thermally Conductive ◽  
Medical Electronic

We developed a thermally conductive and antimicrobial QACs@h-BN/LLDPE composites for thermal management of medically electronic devices, it was approximately 100% against both E. coli and S. aureus and its thermal conductivity can reach 1.115 W m−1 K−1.

Flexible polyurethane/boron nitride composites with enhanced thermal conductivity

2019 ◽  
Vol 32 (3) ◽  
pp. 324-333 ◽  
Author(s):  
Ting Fei ◽  
Yanbao Li ◽  
Baocheng Liu ◽  
Chengbo Xia
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Thermal Management ◽  
High Stability ◽  
Heat Dissipation ◽  
Thermoplastic Polyurethane ◽  
Thermally Conductive ◽  
Mechanical Bending ◽  
Flexible Polyurethane ◽  
Enhanced Thermal Conductivity

Polymer-based composites with high thermal conductivity have great potential application as thermal management materials. This study was devoted to improving the thermal conductivity of the flexible thermoplastic polyurethane (TPU) by employing boron nitride (BN) as heat filler. We prepared flexible and thermally conductive TPU/BN composite via solution mixing and hot pressing. The thermal conductivity of the TPU/BN composite with 50 wt% BN (32.6 vol%) reaches 3.06 W/m·K, approximately 1290% enhancement compared to that of pure TPU (0.22 W/m·K). In addition, the thermal conductivity of our flexible TPU/BN composite with 30 wt% BN is almost not varied (a decrease of only 2.5%) after 100 cycles of mechanical bending, which indicates the high stability of heat conduction of our flexible TPU/BN composite under mechanical bending. The maximum tensile strength of the TPU/BN composite with 5 wt% BN is 48.9 MPa, 14% higher than that of pure TPU (43.2 MPa). Our flexible and highly thermally conductive TPU/BN composites show promise for heat dissipation in various applications in the electronics field.

Epoxy-based thermally conductive adhesives with effective alumina and boron nitride for superconducting magnet

2020 ◽  
Vol 200 ◽  
pp. 108456 ◽  
Author(s):  
Young Jin Hwang ◽  
Jun Min Kim ◽  
Lee Su Kim ◽  
Jae Young Jang ◽  
Myungsu Kim ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Superconducting Magnet ◽  
Conductive Adhesives ◽  
Thermally Conductive

scholarly journals Incorporating MXene into Boron Nitride/Poly(Vinyl Alcohol) Composite Films to Enhance Thermal and Mechanical Properties

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 379
Author(s):  
Seonmin Lee ◽  
Jooheon Kim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Boron Nitride ◽  
Composite Film ◽  
Vinyl Alcohol ◽  
Composite Films ◽  
Poly Vinyl Alcohol ◽  
Thermal And Mechanical Properties ◽  
Conduction Path ◽  
Thermally Conductive

Aggregated boron nitride (ABN) is advantageous for increasing the packing and thermal conductivity of the matrix in composite materials, but can deteriorate the mechanical properties by breaking during processing. In addition, there are few studies on the use of Ti3C2 MXene as thermally conductive fillers. Herein, the development of a novel composite film is described. It incorporates MXene and ABN into poly(vinyl alcohol) (PVA) to achieve a high thermal conductivity. Polysilazane (PSZ)-coated ABN formed a heat conduction path in the composite film, and MXene supported it to further improve the thermal conductivity. The prepared polymer composite film is shown to provide through-plane and in-plane thermal conductivities of 1.51 and 4.28 W/mK at total filler contents of 44 wt.%. The composite film is also shown to exhibit a tensile strength of 11.96 MPa, which is much greater than that without MXene. Thus, it demonstrates that incorporating MXene as a thermally conductive filler can enhance the thermal and mechanical properties of composite films.

scholarly journals Thermal Conductivity and Cure Kinetics of Epoxy-Boron Nitride Composites—A Review

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3634
Author(s):  
John M. Hutchinson ◽  
Sasan Moradi
Keyword(s):  
Thermal Conductivity ◽  
Boron Nitride ◽  
Thermal Management ◽  
Filler Content ◽  
Electronic Devices ◽  
Cure Kinetics ◽  
The Matrix ◽  
Thermally Conductive ◽  
Filler Particles ◽  
Kinetics Of

Epoxy resin composites filled with thermally conductive but electrically insulating particles play an important role in the thermal management of modern electronic devices. Although many types of particles are used for this purpose, including oxides, carbides and nitrides, one of the most widely used fillers is boron nitride (BN). In this review we concentrate specifically on epoxy-BN composites for high thermal conductivity applications. First, the cure kinetics of epoxy composites in general, and of epoxy-BN composites in particular, are discussed separately in terms of the effects of the filler particles on cure parameters and the cured composite. Then, several fundamental aspects of epoxy-BN composites are discussed in terms of their effect on thermal conductivity. These aspects include the following: the filler content; the type of epoxy system used for the matrix; the morphology of the filler particles (platelets, agglomerates) and their size and concentration; the use of surface treatments of the filler particles or of coupling agents; and the composite preparation procedures, for example whether or not solvents are used for dispersion of the filler in the matrix. The dependence of thermal conductivity on filler content, obtained from over one hundred reports in the literature, is examined in detail, and an attempt is made to categorise the effects of the variables and to compare the results obtained by different procedures.

scholarly journals Thermal Properties of Surface-Modified and Cross-Linked Boron Nitride/Polyethylene Glycol Composite as Phase Change Material

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 456
Author(s):  
Jaehyun Wie ◽  
Jooheon Kim
Keyword(s):  
Thermal Conductivity ◽  
Polyethylene Glycol ◽  
Boron Nitride ◽  
Phase Change ◽  
Phase Change Material ◽  
Interfacial Adhesion ◽  
Hydroxyl Groups ◽  
Thermally Conductive ◽  
Surface Modified ◽  
Change Material

A thermally conductive phase change material (PCM) was fabricated using polyethylene glycol (PEG) and boron nitride (BN). However, the interfacial adhesion between the BN and the PEG was poor, hindering efficient heat conduction. Grafting polyvinyl alcohol (PVA) onto the surface of BN and cross-linking due to hydrogen bonding between the hydroxyl groups in PVA and oxygen atoms in PEG improved the wettability of fillers. By employing this strategy, we achieved a thermal conductivity value of 0.89 W/mK, a 286% improvement compared to the thermal conductivity of the pristine PEG (0.23 W/mK). Although the latent heat of composites decreased due to the mobility of the polymer chain, the value was still reasonable for PCM applications.

scholarly journals Achieving a 3D Thermally Conductive while Electrically Insulating Network in Polybenzoxazine with a Novel Hybrid Filler Composed of Boron Nitride and Carbon Nanotubes

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2331
Author(s):  
Yi Wang ◽  
Wei Wu ◽  
Dietmar Drummer ◽  
Chao Liu ◽  
Florian Tomiak ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Boron Nitride ◽  
Condensation Reaction ◽  
Heat Accumulation ◽  
Hybrid Filler ◽  
Excessive Heat ◽  
Hybrid Fillers ◽  
Thermally Conductive ◽  
Treated Carbon

To solve the problem of excessive heat accumulation in the electronic packaging field, a novel series of hybrid filler (BN@CNT) with a hierarchical “line-plane” structure was assembled via a condensation reaction between functional boron nitride(f-BN) and acid treated carbon nanotubes (a-CNTs). The reactions with different mass ratios of BN and CNTs and the effect of the obtained hybrid filler on the composites’ thermal conductivity were studied. According to the results, BN@15CNT exhibited better effects on promoting thermal conductivity of polybenzoxazine(PBz) composites which were prepared via ball milling and hot compression. The thermally conductive coefficient value of PBz composites, which were loaded with 25 wt% of BN@15CNT hybrid fillers, reached 0.794 W· m−1· K−1. The coefficient value was improved to 0.865 W· m−1· K−1 with 15 wt% of BN@15CNT and 10 wt% of BN. Although CNTs were adopted, the PBz composites maintained insulation. Dielectric properties and thermal stability of the composites were also studied. In addition, different thermal conduction models were used to manifest the mechanism of BN@CNT hybrid fillers in enhancing thermal conductivity of PBz composites.

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