Query: boron nitride thermal conductivity

title: Thermal conductivity of 2D nano structured boron nitride (BN) and its composites with polymers
abstract: High thermal conductivity, structural stability, good mechanical and anti oxidant properties makes hexagonal boron nitride (h BN) a promising functional filler for polymers to produce composite materials where excellent thermal management is required, such as in electronic devices. Theoretical studies have revealed that two dimensional (2D) BN has higher thermal conductivity (up to 400 Wm 1 K 1, in plane) than bulk h BN due to a reduction in phonon phonon scattering when scaling down the thickness of the material. For this reason, 2D boron nitride nanosheets (BNNS) are gaining intense interest since they could be utilised in the design of composite materials with excellent efficiency to dissipate heat. Various methods have been explored to produce 2D BNNS including mechanical and chemical exfoliation of pristine bulk BN, chemical reaction, chemical vapour deposition (CVD) and electron irradiation. To facilitate the dispersion of BNNS in polymers, different functionalization strategies have been applied for surface treatment of BNNS. In this review, the different synthesis approaches adopted for BNNS are compared and the effects of BNNS dispersion on the thermal conduction of polymers are discussed. The factors influencing the mechanism of thermal conduction such as materials crystallinity, filler geometry, filler surface functionalization and alignment, filler/matrix interface and processing conditions are discussed. Some perspectives and future directions on how to generate high thermally conductive composites of BNNS and polymer are proposed.

title: Thermal Conductivity and Cure Kinetics of Epoxy Boron Nitride Composites A Review
abstract: 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.

title: 3D graphene and boron nitride structures for nanocomposites with tailored thermal conductivities: recent advances and perspectives
abstract: Various three dimensional (3D) structures are rationally assembled from two dimensional (2D) nanosheets of graphene and boron nitride (BN) for thermal energy regulating applications. The nanocomposites containing these 3D architectures offer thermal conductivities spanning a few orders of magnitude from ultralow values for super thermal insulation to high values for fast heat dissipation. In this review, we summarize the approaches developed to achieve two extremes of thermal conductivity in 3D graphene and BN assemblies by engineering their structures at different length scales. A special focus is placed on identifying key structural parameters affecting the thermal conductivities, including pore morphologies, pore sizes, and cell wall structures. Distinctive applications of 3D graphene and BN structures and their polymer based composites for thermal energy management are highlighted along with their potential multifunctionalities other than thermal conduction or insulation. The in depth understanding of thermal transport properties offer insight into designing novel 3D structures that possess desired thermal conductivities for emerging thermal management applications.

title: Proton conductivity of a hexagonal boron nitride membrane and its energy applications
abstract: Hexagonal boron nitride (h BN) is a promising material for membrane applications due to its high chemical stability in the presence of solvents, outstanding mechanical strength, and high thermal stability. Theoretically, h BN has very small pores (approximately 3.0 A2) at the centers of hexagonal rings formed by the different electron cloud densities of B and N atoms. Through the centers of these rings, h BN allows protons to pass while bigger ions are blocked. It has been demonstrated that h BN exhibits good proton conductivity (approximately 100 mS cm 1) and a separation factor (approximately 10) for protons and deuterons. Furthermore, the van der Waals gaps between layers of 2D materials can be utilized as channels to allow protons to pass while blocking bigger ions. For real world applications, such as fuel cells or batteries, large scale h BN has been applied and exhibited good performance. In this review, we introduce preparation methods for h BN, theoretical calculations of the proton conductivity of h BN, and real world applications of h BN membranes. Finally, we provide additional perspectives regarding h BN membranes.

title: Thermal conductive composites reinforced via advanced boron nitride nanomaterials
abstract: The demand for insulating polymeric composites with high thermal conductivity has increased remarkably for electronic packaging. Since polymers usually suffer from low thermal conductivity, boron nitrides (BN) are emerging as advanced fillers in polymeric composites. BN nanomaterials strikingly reinforce thermal conductivity of polymers and simultaneously improve insulation, thermal expansion, and dielectricity. We herein introduce diverse BN nanomaterials and summarize the progress about thermal conductive composites with various BN fillers from 0D BN particles via 1D nanotubes to 2D nanosheets. 3D fillers, multi scale and multi dimensional mixed BN fillers developed recently are also presented. The functionalization and the controlled orientation of fillers are reviewed, and current challenges towards higher thermal conductivity of BN/polymer composites are additionally discussed.

title: "White graphene" hexagonal boron nitride based polymeric composites and their application in thermal management
abstract: Thermal management is more and more crucial in advanced electronic devices with increasing power density. So, the demand for the materials with high thermal conductivity is rising. Hexagonal boron nitride (h BN) called as "white graphene" has high thermal conductivity of ~2000 W m 1 K 1 (by theoretical calculation) and is an electrical insulator, so h BN filled polymer composite becomes a good candidate for potential employment in heat management of microelectronic devices. This paper gives a brief review on the development of h BN based polymeric composites, including thermal transfer mechanism, fundamental design principle and application, as well as perspectives.

title: Recent progress in polymer dielectrics containing boron nitride nanosheets for high energy density capacitors
abstract: Hexagonal boron nitride nanosheets (BNNSs) are two dimensional nanomaterials with graphitic like layered nanostructures, high surface areas, and large aspect ratios. Owing to their excellent thermal conductivity, electrical and mechanical strengths, BNNSs are emerging as multifunctional fillers in polymer dielectrics. In this article, the authors review the recent progress in the BN containing polymer nanocomposites designed for high performance film capacitors. While general synthetic approaches to BNNSs and polymer/BNNS nanocomposites are summarized, particular attention is placed on structure property correlation and rational structural design of the composites with optimized dielectric properties and capacitive performances. In stark contrast to the polymer composites employing high dielectric constant fillers to enhance the electric displacement, a new design concept based on the utilization of BNNSs with a wide bandgap to impede electrical conduction and consequently improve breakdown strength and charge discharge efficiency of the polymer composites, is highlighted. The significance of developing dielectric capacitors with desirable thermal conductivity and thermal stability to ensure their robust and efficient operation is emphasized. The merits and challenges regarding the existing polymer dielectrics containing BNNSs for energy storage are identified. An outlook for future research opportunities and engineering applications is also presented in this review.

title: Boron nitride based materials for water purification: Progress and outlook.
abstract: Analogous to the carbon family, boron nitride (BN) based materials have gained considerable attention in recent times for applications in various fields. Owing to their extraordinary characteristics, i.e. high surface area, low density, superior thermal stability, mechanical strength, and conductivity, excellent corrosion, and oxidation resistance, the BN nanomaterials have been explored in water remediation. This article critically evaluates the latest development in applications of BN based materials in water purification with focus on adsorption, synthesis of novel membranes and photocatalytic degradation of pollutants. The adsorption of various noxious pollutants, i.e. dyes, organic compounds, antibiotics, and heavy metals from aqueous medium BN based materials are described in detail by illustrating the adsorption mechanism and regeneration potential. The major hurdles and opportunities related to the synthesis and water purification applications of BN based materials are underscored. Finally, a roadmap is suggested for future research to assure the effective applications of BN based materials in water purification. This review is beneficial in understanding the current status of these unique materials in water purification and accelerating the research focusing their future water remediation applications.

title: Nanostructured boron nitride based materials: synthesis and applications
abstract: Nanocomposite materials are widely studied because of their unique design opportunities and properties. They can be classified into three main groups in function of the matrix used: polymer based, ceramic based, and metal based nanocomposites. The nanofiller choice is one of the most important steps because it will improve the nanocomposite properties. This review focuses on boron nitride as nanofiller because of its extraordinary properties: high thermal and chemical stability, good mechanical strength, superior resistance to oxidation, good thermal conductivity, and electrical insulation. The goal of this review is to provide an overview on the synthesis methods to produce boron nitride based nanocomposites, particularly polymer and ceramic based nanocomposites, and on their potential applications in promising fields, such as energy, environment, and health.

title: Boron nitride nanocomposites for microwave absorption: A review
abstract: In the past decades, great progress in electromagnetic microwave absorption (MA) materials in both civil and military fields have been made due to the high demand for the elimination of electromagnetic interference. Recently, hexagonal boron nitride (h BN) based materials have been regarded as one of the promising MA composite materials since their remarkable dielectric property, excellent thermal conductivity, low density and outstanding chemical stability. Developing efficient h BN based MA materials has aroused wide interest, aiming to achieve ideal MA materials with thin thickness, low density, high thermal stability, strong absorption capacity, wide absorption bandwidth, and low filling rate. This review presents an overview of the progresses in h BN based MA materials. It starts with a brief introduction of the MA mechanism, followed by reviewing the fabrication and potential application of different h BN based MA materials. Finally, the research perspectives on the h BN based MA materials are proposed. It is expected that the research interest in h BN based MA materials from the basic fabrication to engineering application will be instigated in future.