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Highlights This study explores the development of nanocomposites by incorporating multi‐walled carbon nanotubes (MWCNT), titanium nitride (TiN), and cubic boron nitride (c‐BN) nano powders into photo‐polymer epoxy resins for use in Stereolithography (SLA) additive manufacturing. Mechanical and thermal properties were systematically investigated to assess their performance. Initially, MWCNT, TiN, and c‐BN nano powders were homogeneously mixed with the resin to ensure uniformity. The resulting mixtures were then processed using SLA technology to evaluate production quality and material performance. The study revealed significant improvements in mechanical and thermal properties compared to pure resin, aligning with previous research outcomes. Specifically, the incorporation of MWCNT led to a notable enhancement in thermal conductivity, showing an increase of 24.21% as the thermal conductivity coefficient increased from 0.19 to 2.36 W/m·k. On the other hand, c‐BN significantly boosted mechanical strength, resulting in a substantial 20.45% increase as the shore D hardness went from 88.53 to 106.64. These findings highlight the promising potential of nanocomposites across various industries including electronics, aerospace, automotive, construction, medical devices, and manufacturing. Developed nanocomposites with MWCNT, TiN, and c‐BN in SLA resin. c‐BN increased hardness by 20.45%, proving its effectiveness in composites. MWCNT enhanced thermal conductivity by 24.21%, boosting material performance. Pioneering use of TiN and c‐BN in SLA, addressing gaps in existing research. Applications span electronics, aerospace, automotive and medical devices. [ABSTRACT FROM AUTHOR]

This study aims to explore Pickering emulsion stabilized by hexagonal boron nitride (h-BN) mixed with styrene/maleic anhydride and fabricate melamine–urea–formaldehyde (MUF)/paraffin microcapsules for thermal management applications. The particle size distribution and morphology of h-BN were observed, respectively, by a laser-diffraction particle size analyzer and a transmission electron microscope. Field emission scanning electron microscope, X-ray diffractometer, Fourier transform infrared spectroscope, differential scanning calorimeter, and thermogravimetric analyzer were applied to determine the morphologies, crystallography, chemical components, phase change properties, and thermal stability of MUF/paraffin microcapsules with different h-BN dosages. It was found that the h-BN dosage of 0.05 g achieved the encapsulation ratio of 58.08%, melting enthalpy of 107.90 J/g, and crystallization enthalpy of 107.70 J/g. When the MUF/paraffin microcapsules were applied in calcium sulfate dehydrate (CS), CS/MicroC01 demonstrated high potential in thermal management of buildings. [ABSTRACT FROM AUTHOR]

Epoxy resins (EPs) are highly coveted as insulating materials for engineering applications. However, their limited mechanical properties and inadequate thermal conductivity at cryogenic temperatures significantly restrict their range of applications. Herein, a novel approach was introduced for crafting EP composites infused with boron nitride (BN) using hyperbranched polymer (HBP) grafting. The resulting HBP‐BN was uniformly dispersed within the EP and securely bonded to the matrix through robust chemical interactions, significantly improving the property enhancement efficiency of HBP‐BN on EP. Thus, the mechanical strength of EP/HBP‐BN composites was significantly enhanced, with maximum tensile and impact strengths achieved at 6 and 4 wt% HBP‐BN content. These values exceeded those of pure EP by 47% and 22% at room temperature (RT) and increased even more substantially to 72% and 135% at 77 K. Moreover, the composite demonstrated a remarkable 430% improvement in thermal conductivity, reaching 1.1627 W·m−1·K−1, when the HBP‐BN content reached 40 wt%. Simultaneously, EP/HBP‐BN composites exhibit low dielectric permittivity and high volume resistivity, signifying exceptional electrical insulation properties. HBP‐BN substantially enhances the cryogenic properties of EP composites, offering an efficient pathway for the utilization of EPs in engineering applications. Highlights: A novel method to enhance the cryogenic properties of EP was introduced.HBP‐BN significantly improves the cryogenic properties in EP composites.The composites are of significant interest for various engineering applications. [ABSTRACT FROM AUTHOR]

Thermally conductive polymeric composites with low dielectric constant are highly promising for the packaging materials in the field of modern communication. Therefore, the synergistic improvement of low dielectric constant and high thermal conductivity has become a current research hotspot. In this work, we propose a one‐step alkylation of boron nitride nanosheet (BNNS) with ultrasonic stratification using 1‐hexanol, and then hot press the films to make Alkyl‐BNNSs orient in the fluorinated polyimide (f‐PI). The resulting Alkyl‐BNNS/f‐PI composite successfully realizes the synergistic improvement of thermal property and dielectric properties, exhibiting a high heat conductivity coefficient of 2.36 Wm−1 K−1 with a filler content of 4.99 wt.%. Moreover, the permittivity and dielectric loss of the film are as low as 1.76 and 0.0065 at 1 MHz, respectively. This work provides a facile strategy for breaking the bottleneck of making polyimide composites simultaneously with high thermal conduction and low dielectric performance. Highlights: The composite exhibits a high heat‐conducting coefficient of 2.36 Wm−1 K−1.Ultra‐low dielectric constant of 1.76 was achieved by the modification of film.Excellent breakdown resistance and flexibility were endowed with the composites. [ABSTRACT FROM AUTHOR]

Recent advances have shown the beneficial impact of adding nanoparticles to thermal oil. Diamond and boron nitride nanoparticles have superior thermal conductivity and excellent thermal and optical properties. In the current study, thermal conductivity, specific heat, and rheological behavior of diamond and boron nitride-based hybrid nanofluids in thermal oil are experimentally investigated for 0%, 0.2%, 0.4%, and 0.6% weight concentrations and a wide range of temperatures. The proportion between diamond and boron nitride utilized in the study is 1:1. A two-step method is applied to prepare stable hybrid nanofluids. The obtained data indicate that the hybrid nanofluids' thermal conductivity and specific heat enhance with increasing temperature and weight concentration. Almost 37.4% and 48.1% enhancement is observed in the thermal conductivity and specific heat, respectively, at 65 °C and 0.6% weight concentration. Thermal oil-based hybrid nanofluids display Newtonian behavior at low shear rates and an inverse relationship with temperature. Shear-thinning non-Newtonian behavior is observed at high shear rates and temperatures. A maximum increase in viscosity up to 22.0% is observed at 65 °C and 0.6% wt. concentration. The relative change indicates that all investigated properties have a significant impact, where the increasing trend of thermal conductivity and specific heat with increasing temperature and weight concentration of thermal oil-based hybrid nanofluids make them suitable for high-temperature heat transfer applications. [ABSTRACT FROM AUTHOR]

Owing to the rapid advancement in electronic devices, thermal interface materials have been introduced to solve the thermal dissipation and electrical insulation problems in electronic parts and packaging materials. In this study, flexible thermally conductive acrylate‐based composites were fabricated via 3D vat photopolymerization. The effects of amine functional groups on the thermal and mechanical properties of acrylate polymers were explored. Surface‐treatment agents, namely, (3‐aminopropyl)triethoxysilane (APTES) and octadecylamine (ODA), were selected to enhance the poor dispersibility of fillers in the resin matrix caused by aggregation. The APTES‐treated carbon nanotube (CNT)–boron nitride (BN) hybrid composite exhibited the highest thermal conductivity of 0.990 W m−1 K−1, which was remarkably 482.35% higher than that of the matrix owing to the addition of 30 wt% BN, 0.5 wt% CNTs, and APTES treatment. The ODA‐treated CNT composite, which contained only 0.5 wt% CNTs, exhibited a thermal conductivity of 0.540 W m−1 K−1, which was 217.65% higher than that of the matrix. The electrical insulation properties of the composites were characterized, and the composites exhibited low electrical conductivity as electrical insulation materials. The advantages of the 3D‐printed flexible thermally conductive acrylate polymers usher in a new era of using polymer composites to address heat dissipation problems in complex structures. [ABSTRACT FROM AUTHOR]

In the realm of thermal interface materials (TIMs), high thermal conductivity and low density are key for effective thermal management and are particularly vital due to the growing compactness and lightweight nature of electronic devices. Efficient directional arrangement is a key control strategy to significantly improve thermal conductivity and comprehensive properties of thermal interface materials. In the present work, drawing inspiration from natural leaf and branch structures, a simple-to-implement approach for fabricating oriented thermal conductivity composites is introduced. Utilizing carbon fibers (CFs), known for their ultra-high thermal conductivity, as branches, this design ensures robust thermal conduction channels. Concurrently, boron nitride (BN) platelets, characterized by their substantial in-plane thermal conductivity, act as leaves. These components not only support the branches but also serve as junctions in the thermal conduction network. Remarkably, the composite achieves a thermal conductivity of 11.08 W/(m·K) with just an 11.1 wt% CF content and a 1.86 g/cm3 density. This study expands the methodologies for achieving highly oriented configurations of fibrous and flake materials, which provides a new design idea for preparing high-thermal conductivity and low-density thermal interface materials. [ABSTRACT FROM AUTHOR]

As one of the emerging nanomaterials, boron nitride nanotubes (BNNTs) provide promising opportunities for diverse applications due to their unique properties, such as high thermal conductivity, immense inertness, and high-temperature durability, while the instability of BNNTs due to their high surface induces agglomerates susceptible to the loss of their advantages. Therefore, the proper functionalization of BNNTs is crucial to highlight their fundamental characteristics. Herein, a simplistic low-cost approach of BNNT surface modification through catechol-polyamine (CAPA) interfacial polymerization is postulated to improve its dispersibility on the polymeric matrix. The modified BNNT was assimilated as a filler additive with AlN/Al2O3 filling materials in a PDMS polymeric matrix to prepare a thermal interface material (TIM). The resulting composite exhibits a heightened isotropic thermal conductivity of 8.10 W/mK, which is a ~47.27% increase compared to pristine composite 5.50 W/mK, and this can be ascribed to the improved BNNT dispersion forming interconnected phonon pathways and the thermal interface resistance reduction due to its augmented compatibility with the polymeric matrix. Moreover, the fabricated composite manifests a fire resistance improvement of ~10% in LOI relative to the neat composite sample, which can be correlated to the thermal stability shift in the TGA and DTA data. An enhancement in thermal permanence is stipulated due to a melting point (Tm) shift of ∼38.5 °C upon the integration of BNNT-CAPA. This improvement can be associated with the good distribution and adhesion of BNNT-CAPA in the polymeric matrix, integrated with its inherent thermal stability, good charring capability, and free radical scavenging effect due to the presence of CAPA on its surface. This study offers new insights into BNNT utilization and its corresponding incorporation into the polymeric matrix, which provides a prospective direction in the preparation of multifunctional materials for electric devices. [ABSTRACT FROM AUTHOR]

Two‐dimensional hexagonal boron nitride (hBN) based nanocomposites exhibit excellent mechanical and thermal properties for various electronics, automotive, and aerospace applications. The present work gives a novel approach to fabricating hexagonal boron nitride/epoxy nanocomposites using isopropanol and dimethyl ketone as dispersants in two different routes and to predict mechanical characteristics employing deep learning and machine learning models. Nanocomposites were fabricated by employing casting techniques with varying concentrations of hBN, spanning from 0.25 to 1 wt%, utilizing dispersing solvents. The nanocomposites were analyzed for mechanical behavior, highlighting a notable improvement in the mechanical properties at 0.5 wt% isopropanol dispersed hBN. It showcased 61% improvement in tensile strength, 38.41% increase in flexural strength, and 35.80% increase in flexural modulus respectively as compared to the pristine epoxy. The Halpin Tsai analytical model showed agreement with the elastic modulus calculated experimentally. The fractured SEM micrograph supported the improved dispersion of the hBN nanocomposite. Thermal stability of 0.5 wt% isopropanol dispersed hBN/epoxy nanocomposite revealed an improvement by 8°C at 50% degradation as compared to the pristine epoxy. Linear regression, random forest regression, support vector regression, and deep neural network (DNN) were employed to predict values. DNN proved better results by showcasing low prediction loss and high R2 values (0.99468–0.99966). Highlights: hBN/epoxy nanocomposite with isopropanol and dimethyl ketone as dispersants.0.5% hBN loading in isopropanol exhibited improved mechanical characteristics.The Halpin Tsai model was employed for evaluating theoretical elastic modulus.Improved thermal stability and filler dispersion by optimized hBN/epoxy combination.Deep neural network showed higher R2 value and lower prediction loss. [ABSTRACT FROM AUTHOR]

Traditional thermally conductive materials are gradually losing their advantages as the electronics industry develops rapidly. Polymers are in urgent need of a material with high thermal conductivity, stable structure, good mechanical properties and oxidation resistance, which makes hexagonal boron nitride (h-BN) an excellent heat transfer filler for polymer composites. Boron nitride nanosheets (BNNS) are monolayers of hexagonal boron nitride, and theoretical studies have shown that BNNS have a higher thermal conductivity than h-BN (up to 400Wm-1K-1, in-plane). This paper provides a comprehensive review of various methods for preparing BNNS, including mechanical exfoliation, liquid phase sonication exfoliation and chemical vapor deposition (CVD). In addition, various factors affecting the thermal conductivity of BNNS, including grain boundary, grain size and defects, are also discussed. Then, the influence of BNNS as filler on the thermal conductivity of the polymer was further discussed. Finally, this paper summarizes the existing BNNS applications and lists the application scenarios of BNNS in various fields. The purpose of this review is to summarize the previous work and put forward the prospect and future development direction of preparing high thermal conductivity BNNS-included polymer composites, so as to stimulate the research and improvement of new preparation methods for BNNS and promote its practical application as heat transfer materials. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of the addition of hexagonal boron nitride (hBN) and/or graphene nanoplatelets (GnP) to basalt fiber (BF)-reinforced polyphenylene sulfide (PPS) matrix composites at different weight ratios, both alone and hybrid, on the composite properties. Mechanical, tribological, thermal, and thermomechanical properties of the composites were evaluated using analyses such as tensile test at different ambient temperatures (23 °C and 70 °C), adhesive wear test, thermogravimetric analysis, differential scanning calorimeter analysis, and dynamic mechanical analysis. The results of the tensile test at 70 °C showed that the addition of 0.3 wt% GnP and 1 wt% hBN to the BF-reinforced composites resulted in a 40% increase in tensile strength. In addition, the composite containing 0.3 wt% GnP and 10 wt% hBN showed a 25% increase in high-temperature tensile strength, a 37% decrease in COF value, and a 10 °C improvement in T40% thermal decomposition temperature. Furthermore, the analysis results showed that the hybrid inclusion of GnP and hBN to the BF-reinforced PPS matrix composites improved the high-temperature tensile strength, adhesive wear resistance and thermal resistance properties. As a result, it is concluded that the hybrid use of GnP and hBN provides superior properties to the composites for advanced composite applications where mechanical, tribological and thermal performance is required along with electrical properties. [ABSTRACT FROM AUTHOR]

With the trend of integration and miniaturization of stretchable electronics, thermal management has been a crucial issue. Developing novel materials with high thermal conductivity (TC) and flexibility is urgent. Herein, we report a stretchable polydimethylsiloxane (PDMS)/boron nitride nanosheet (BNNS)@spherical aluminum oxide (Al2O3) composite with high TC and electrical insulation prepared by a two‐step strategy of sucrose‐template and hot‐pressing. An effective foam‐pressing route benefits the composites to form a three‐dimensional thermally conductive networks, improving the in‐plane TC value of the resultant composite to 4.03 W/(mK) at the filler mass fraction of 35.7 wt% and enhancing to 4.66 W/(mK) under 40% stretching ratio. Meanwhile, the composites can be restored to their former state and retain thermally conductive stability with repeated bending and twisting tests. Moreover, the composites were applied in LED with stretching, exhibiting good heat dissipation performance. These results demonstrate this PDMS composite can be potentially utilized as a high‐performance material to solve thermal management problems in flexible electronics. Highlights: The heat conduction network is prepared by sucrose‐template and hot‐pressing.BNNS@P‐Al2O3 fillers are self‐assembled via the electrostatic interaction.The composites exhibit good thermal conduction and superior flexibility.The thermal conductivity of the composite increases after stretching.The composites can retain thermal conductive stability after deformation. [ABSTRACT FROM AUTHOR]

With the development of high-voltage and high-power devices in the direction of compactness, lightness and extreme working environments, the contradiction between thermal conductivity and dielectric breakdown strength is becoming more and more obvious. In this work, a novel boron nitride nanosheet with uniformly dispersed diamond nanocrystalline (abbreviated as BA@DN) was prepared via facile acidizing hydroxylation, in situ copolymerization self-assembly of dopamine and blending process. The obtained hybrid filler was employed to embed into epoxy matrix, showing enhanced thermal conductivity and sufficient dielectric breakdown strength. For example, the through-plane and inplane thermal conductivity of epoxy composite with 5% BA@DN-2 reaches to 0.56 and 3.824 W/m K, respectively. The study proposes a modified plane thermal conductivity model. Based on calculations, it was found that the modified thermal conductivity of 5% BA@DN-2 is 3.47 W/m K, which is significantly higher than that of pure EP, specifically 17.35 times higher. These findings are significant in terms of materials science. while its alternating current and direct current dielectric breakdown strength are 48.84 and 136.31 kV/mm, about 85.68% and 99.1% of pure epoxy, respectively. The mechanism of outstanding dielectric breakdown strength was analyzed via dielectric characteristic, partial discharge performance and the theory of quantum size effect. In addition, a modified multi-core model with a multilevel overlapping interface is presented. Highlights • The acidified diamond nanocrystals (DNs) were attached to dopaminecoated boron nitride nanocrystals by a blending process. • The small size effect of DNs allows the epoxy film to have both high thermal conductivity and high insulation properties. • A thermal conductivity correction model is proposed to eliminate the effect of graphite layer on the film. [ABSTRACT FROM AUTHOR]

To find a low temperature phase change material (PCM) that can be applied to the middle constant temperature chamber of the three chamber refrigerator, this study proposes a binary eutectic PCM of n-decanol and capric acid as a base liquid, expanded graphite as a support material, and boron nitride as a thermal conductivity enhanced particle to modify the material. The composite PCM with suitable phase change temperature and high phase change latent heat is prepared by the solution blending method. The leakage rate experiment determines the maximum adsorption ratio of expanded graphite to be 92 %. The chemical structure, microstructure and thermodynamic properties are characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, thermal conductivity analyzer and thermogravimetric analyzer. The results show that the n-decanol and capric acid binary eutectic PCM is fully wrapped in the porous structure of expanded graphite, and boron nitride thermal conductivity enhanced particles are well adsorbed on the surface and pores of expanded graphite. The n-decanol and capric acid phase change material, boron nitride thermal conductivity enhanced particles and expanded graphite support material are only physically combined and no chemical reaction occurred. The phase change temperature of CPCM-2 with 3 % boron nitride thermal conductivity enhanced particles is -3.68 °C, the phase change latent heat is 129.2 J/g, and the thermal conductivity is 0.75 W/m·K. It has good thermal stability and reliability in the application temperature range.

Abstract Prototype development nowadays can rarely be imagined without 3D printing. In the fast‐moving electronics industry, 3D printing is a good way to react quickly to changing developments, for example, when it comes to heat sinks made of thermally conductive material. 3D printing of thermally conducting plastics, which are also electrically insulating, is an ideal candidate for the rapid generation of heat sink. Nevertheless, 3D printing also shows some drawbacks in regard to properties of the printed parts, as porosities or layer adhesion, emerging from layer deposition in the process. Therefore, the aim of this work was to investigate the influence of the orientation of fillers on the thermal conductivity of filled polylactic acid (PLA). PLA was filled with amounts of 15–45 wt.% of boron nitride and aluminum granules and printed into heat sinks in two different orientations to investigate this influence on the thermal conductivity. The printed heat sinks were then placed on a heated aluminum block and the thermal transport was examined with an infrared camera. It could be shown that especially with platelet‐shaped fillers such as boron nitride, the orientation of these in the test specimen has a large influence on the thermal conductivity. Highlights 3D printing of thermally conductive heat sinks Thermal characterization of 3D printed heat sinks Computer tomography scans of heat sinks to evaluate the porosity

To find a low temperature phase change material (PCM) that can be applied to the middle constant temperature chamber of the three chamber refrigerator, this study proposes a binary eutectic PCM of n-decanol and capric acid as a base liquid, expanded graphite as a support material, and boron nitride as a thermal conductivity enhanced particle to modify the material. The composite PCM with suitable phase change temperature and high phase change latent heat is prepared by the solution blending method. The leakage rate experiment determines the maximum adsorption ratio of expanded graphite to be 92 %. The chemical structure, microstructure and thermodynamic properties are characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, thermal conductivity analyzer and thermogravimetric analyzer. The results show that the n-decanol and capric acid binary eutectic PCM is fully wrapped in the porous structure of expanded graphite, and boron nitride thermal conductivity enhanced particles are well adsorbed on the surface and pores of expanded graphite. The n-decanol and capric acid phase change material, boron nitride thermal conductivity enhanced particles and expanded graphite support material are only physically combined and no chemical reaction occurred. The phase change temperature of CPCM-2 with 3 % boron nitride thermal conductivity enhanced particles is -3.68 °C, the phase change latent heat is 129.2 J/g, and the thermal conductivity is 0.75 W/m·K. It has good thermal stability and reliability in the application temperature range. [ABSTRACT FROM AUTHOR]

Prototype development nowadays can rarely be imagined without 3D printing. In the fast‐moving electronics industry, 3D printing is a good way to react quickly to changing developments, for example, when it comes to heat sinks made of thermally conductive material. 3D printing of thermally conducting plastics, which are also electrically insulating, is an ideal candidate for the rapid generation of heat sink. Nevertheless, 3D printing also shows some drawbacks in regard to properties of the printed parts, as porosities or layer adhesion, emerging from layer deposition in the process. Therefore, the aim of this work was to investigate the influence of the orientation of fillers on the thermal conductivity of filled polylactic acid (PLA). PLA was filled with amounts of 15–45 wt.% of boron nitride and aluminum granules and printed into heat sinks in two different orientations to investigate this influence on the thermal conductivity. The printed heat sinks were then placed on a heated aluminum block and the thermal transport was examined with an infrared camera. It could be shown that especially with platelet‐shaped fillers such as boron nitride, the orientation of these in the test specimen has a large influence on the thermal conductivity. Highlights: 3D printing of thermally conductive heat sinksThermal characterization of 3D printed heat sinksComputer tomography scans of heat sinks to evaluate the porosity [ABSTRACT FROM AUTHOR]

Polyimide-based composite films with high thermal conductivity, good mechanical property and electrical insulating performance are urgently needed in the electronics and microelectronics fields. As one of the key technical challenges to be solved, interfacial compatibility between filler and matrix plays an important role for composite film. Herein, boron nitride was modified by grafting polyimide brushes via a two-step method, and a series of thermally conductive polyimide/boron nitride composite films were prepared. Both characterization and performance results proved that the interfacial interaction and compatibility was greatly enhanced, resulting in a significant reduction in defects and interfacial thermal resistance. The interphase width of transition zone between two phases was also efficiently enlarged due to polyimide brushes grafted on filler surface. As a result, composite films based on polyimide-grafted boron nitride exhibited significantly improved properties compared with those based on pristine filler. Tensile strength can reach up to 80 MPa even if the filler content is as high as 50 wt%. The out-of-plane and in-plane thermal conductivity of composite film increased to 0.841 and 0.850 W·m−1·K−1, respectively. In addition, thermal and dielectric properties of composite films were also enhanced to some extent. The above results indicate that surface modification by chemically grafting polymer brushes is an effective method to improve two-phase interfacial compatibility so as to prepare composite film with enhanced properties. [ABSTRACT FROM AUTHOR]

With the rapid development of the electronics, communication, and energy industries, there is an increasing demand for flexible materials with high thermal conductivity and electrical insulation properties. Silicone rubber (SR) is widely used in various fields due to its excellent mechanical properties. However, its intrinsic low thermal conductivity requires the addition of thermally conductive fillers to enhance its thermal conductivity. Insulating thermally conductive composites are prepared by adding thermally conductive fillers such as boron nitride (BN) and graphite into a silicone rubber matrix. When BN is added as a single filler up to 20 wt%, the thermal conductivity of BN/SR reaches 0.526 W m−1 K−1, which is a 126% improvement compared to the SR matrix. When the total filler content is 20 wt%, and the ratio of BN to graphite is 1:1, the thermal conductivity of BN/graphite/SR composite is 0.685 W m−1 K−1. This represents a 194% and 30% increase in thermal conductivity compared to the SR matrix and BN/SR composite with the same filler content, respectively. On the cured silicone rubber substrate, the incremental cured BN/SR acts as an insulation coating. This allows for a significant reduction in the electrical conductivity of the composite without the use of adhesives, while preserving the thermal conductivity. Moreover, the interface formed through incremental curing retains high tensile and compressive strength. [ABSTRACT FROM AUTHOR]

For the removal of elevated thermal flux in high‐temperature applications, there is an urgent need for robust and lightweight thermally conductive thermoplastic materials with suitable mechanical integrity. In current work, multiscale hexagonal boron nitride (hBN) and titanium dioxide (TiO2) fillers are integrated into polyetheretherketone (PEEK) polymer to create a synergistic effect regarding thermal conductivity. An optimized twin‐screw extrusion is utilized to disperse the fillers uniformly in the host polymer by changing the screw design in terms of kneading, mixing, and reverse elements, feeding zones of the fillers/polymer, and the feeding cycles. Various specimens were developed by systematically varying the relative filler amount of the thermally anisotropic hBN and the thermally isotropic TiO2, while the total filler content was fixed to 60 wt%. As a result, 50B‐10T composite exhibited an ultrahigh thermal conductivity of 8.195 W/(m.K), with a 3139% enhancement compared to unfilled PEEK. Moreover, as the PEEK‐mediated regions are occupied with nano‐sized TiO2, efficient channels for phonon transport are formed between hybrid fillers, and the through‐plane thermal conductivity reached 1.704 W/(m.K) in 50B‐10T sample. The potential application of prepared composites as a heat spreader is demonstrated by monitoring surface temperature distribution and numerical simulation. Meanwhile, we achieved a synchronous improvement in mechanical stiffness within hybrid composites; and failure mechanisms including crack bridging at TiO2‐PEEK interface, and debonding at hBN‐PEEK interface are observed in hybrid composites. Lastly, the high thermal stability makes the PEEK/hBN/TiO2 specimens suitable for heat dissipation in demanding applications in the energy and aerospace sectors. Highlights: Bespoke screw design developed for scalable manufacturing of Polyetheretherketone (PEEK) matrix composites reinforced with Hexagonal Boron Nitride (hBN) and Titanium Dioxide (TiO2) via twin‐screw melt compounding.Interconnected 3D filler networks were achieved due to the filler dimension effect, allowing us to reach an ultrahigh in‐plane thermal conductivity value of 8.2 W/(m.K) and through‐plane thermal conductivity value of 1.7 W/(m.K) for 50B‐10T specimen.Manufactured hybrid PEEK/hBN/TiO2 composite specimens possess excellent mechanical stiffness. [ABSTRACT FROM AUTHOR]

In order to solve the problems of low thermal conductivity and easy liquid leakage of a stearic acid (SA), the composite phase change material(PCM) was prepared by adding boron nitride (BN) and expanded graphite (EG) to melted SA, and its thermal conductivity, crystal structure, chemical stability, thermal stability, cycle stability, leakage characteristics, heat storage/release characteristics, and temperature response characteristics were characterized. The results showed that the addition of BN and EG significantly improved the thermal conductivity of the material, and they efficiently adsorbed melted SA. The maximum load of SA was 76 wt. % and there was almost no liquid leakage. Moreover, the melting enthalpy and temperature were 154.20 J • g − 1 and 67.85°C, respectively. Compared with pure SA, the SA/BN/EG composite showed a lower melting temperature and a higher freezing temperature. In addition, when the mass fraction of BN and EG was 12 wt. %, the thermal conductivity of the composite was 6.349 W • m−1 • K−1, which was 18.619 times that of SA. More importantly, the composite showed good stability for 50 cycles of heating and cooling, and the SA / BN / EG-12 hardly decomposes below 200°C, which implies that the working performance of the composite PCM is relatively stable within the temperature range of 100°C. Therefore, the composite can exhibit excellent thermal stability in the field of building heating.

Highlights: A core-sheath structured coaxial composite fiber with highly aligned and densely stacked boron nitride nanosheets arrangements in the sheath was successfully fabricated. The coaxial fibers have an ultrahigh axial Herman orientation parameter of 0.81, thermal conductivity of 17.2 W m−1 K−1, and tensile strength of 192.5 MPa. The coaxial fibers exhibit intensively potential applications in the wearable thermal management textile. Hexagonal boron nitride nanosheets (BNNSs) exhibit remarkable thermal and dielectric properties. However, their self-assembly and alignment in macroscopic forms remain challenging due to the chemical inertness of boron nitride, thereby limiting their performance in applications such as thermal management. In this study, we present a coaxial wet spinning approach for the fabrication of BNNSs/polymer composite fibers with high nanosheet orientation. The composite fibers were prepared using a superacid-based solvent system and showed a layered structure comprising an aramid core and an aramid/BNNSs sheath. Notably, the coaxial fibers exhibited significantly higher BNNSs alignment compared to uniaxial aramid/BNNSs fibers, primarily due to the additional compressive forces exerted at the core-sheath interface during the hot drawing process. With a BNNSs loading of 60 wt%, the resulting coaxial fibers showed exceptional properties, including an ultrahigh Herman orientation parameter of 0.81, thermal conductivity of 17.2 W m−1 K−1, and tensile strength of 192.5 MPa. These results surpassed those of uniaxial fibers and previously reported BNNSs composite fibers, making them highly suitable for applications such as wearable thermal management textiles. Our findings present a promising strategy for fabricating high-performance composite fibers based on BNNSs. [ABSTRACT FROM AUTHOR]

In a recent experimental accomplishment, a two-dimensional holey graphyne semiconducting nanosheet with unusual annulative π-extension has been fabricated. Motivated by the aforementioned advance, herein we theoretically explore the electronic, dynamical stability, thermal and mechanical properties of carbon (C) and boron nitride (BN) holey graphyne (HGY) monolayers. Density functional theory (DFT) results reveal that while the C-HGY monolayer shows an appealing direct gap of 1.00 (0.50) eV according to the HSE06(PBE) functional, the BNHGY monolayer is an indirect insulator with large band gaps of 5.58 (4.20) eV. Furthermore, the elastic modulus (ultimate tensile strength) values of the single-layer C- and BN-HGY are predicted to be 127(41) and 105(29) GPa, respectively. The phononic and thermal properties are further investigated using machine learning interatomic potentials (MLIPs). The predicted phonon spectra confirm the dynamical stability of these novel nanoporous lattices. The room temperature lattice thermal conductivity of the considered monolayers is estimated to be very close, around 14.0 ± 1.5 W/mK. At room temperature, the C-HGY and BN-HGY monolayers are predicted to yield an ultrahigh negative thermal expansion coefficient, by more than one order of magnitude larger than that of the graphene. The presented results reveal decent stability, anomalously low elastic modulus to tensile strength ratio, ultrahigh negative thermal expansion coefficients and moderate lattice thermal conductivity of the semiconducting C-HGY and insulating BN-HGY monolayers. [ABSTRACT FROM AUTHOR]

Inorganic aerogels have exhibited many superior characteristics with extensive applications, but are still plagued by a nearly century-old tradeoff between their mechanical and thermal properties. When reducing thermal conductivity by ultralow density, inorganic aerogels generally suffer from large fragility due to their brittle nature or weak joint crosslinking, while enhancing the mechanical robustness by material design and structural engineering, they easily sacrifice thermal insulation and stability. Here, we report a chemically bonded multi-nanolayer design and synthesis of a graphene/amorphous boron nitride aerogel to address this typical tradeoff to further enhance mechanical and thermal properties. Attributed to the chemically bonded interface and coupled toughening effect, our aerogels display a low density of 0.8 mg cm−3 with ultrahigh flexibility (elastic compressive strain up to 99% and bending strain up to 90%), and exceptional thermostability (strength degradation <3% after sharp thermal shocks), as well as the lowest thermal conductivities in a vacuum (only 1.57 mW m−1 K−1 at room temperature and 10.39 mW m−1 K−1 at 500°C) among solid materials to date. This unique combination of mechanical and thermal properties offers an attractive material system for thermal superinsulation at extreme conditions. [ABSTRACT FROM AUTHOR]

The use of polylactic acid‐based composites as self‐fixing materials is a promising technology for various applications due to the shape memory effect of polylactide. In this study, hexagonal boron nitride (h‐BN) was mixed with polylactic acid (PLA) with concentrations of 0, 0.5, 1, 2, 5, and 10 wt% for subsequent film casting. The morphology, mechanical and thermal characteristics of the composite were investigated. With a high percentage of filler content, a decrease in thermal conductivity was observed. The recovery strain decreased with increasing the filler content. The amount of h‐BN had a mixed effect on the recovery stress of the composite. Thus, PLA/h‐BN composites represent a new research idea to study the influence of a heat‐conducting filler on a shape memory effect in polylactic acid. Highlights: Correlation between crystallinity, thermal and shape memory properties was describedDecrease in thermal conductivity was observed with the large percentage of fillingThe composite with 2 wt% of h‐BN exhibits optimal characteristics of SMERecovery strain decreased with the rise of filler contentAmount of h‐BN had a non‐trivial effect on the recovery stress of composite [ABSTRACT FROM AUTHOR]

Due to its mechanical, rheological, and chemical properties, high-density polyethylene (HDPE) is commonly used as a material for producing the pipes for transport of various media. Low thermal conductivity (0.4 W/mK) narrows down the usage of HDPE in the heat exchanger systems. The main goal of the work is to reduce the vertical depth of the HDPE pipe buried in the borehole by increasing the thermal conductivity of the material. This property can be improved by adding certain additives to the pure HDPE matrix. Composites made of HDPE with metallic and non-metallic additives show increased thermal conductivity several times compared to the thermal conductivity of pure HDPE. Those additives affect the mechanical properties too, by enhancing or degrading them. In this research, the thermal conductivity and tensile properties of composite made of HDPE matrix and two types of additives, expanded graphite (EG) and boron nitride (BN), were tested. Micro-sized particles of EG and two different sizes of BN particles, micro and nano, were used to produce composite. The objective behind utilizing composite materials featuring dual additives is twofold: firstly, to enhance thermal properties, and secondly, to improve mechanical properties when compared with the pure HDPE. As anticipated, the thermal conductivity of the composites exhibited an eightfold rise in comparison to the pure HDPE. The tensile modulus experienced augmentation across all variations of additive ratios within the composites, albeit with a marginal reduction in tensile strength. This implies that the composite retains a value similar to pure HDPE in terms of tensile strength. Apart from the enhancement observed in all the aforementioned properties, the most significant downside of these composites pertains to their strain at yield, which experienced a reduction, declining from the initial 8.5% found in pure HDPE to a range spanning from 6.6% to 1.8%, dependent upon the specific additive ratios and the size of the BN particles. [ABSTRACT FROM AUTHOR]

The accumulation of heat in electronic devices puts forward an urgent demand for thermal interface materials. It is still a great challenge to achieve the good comprehensive performance of high thermal conductivity (TC), insulation, flexibility and tensile strength. In this work, polyester‐based nonwoven fabric (NWF) was coated with boron nitride nanosheets (BNNS) by dispersion and interfacial reinforcement of cellulose nanofibers to obtain a three‐dimensional thermally conductive network skeleton (BNNS@NWF). The sandwich‐structured composite film was assembled by introducing alumina (Al2O3)/polydimethylsiloxane (PDMS) layers on the top and bottom surfaces of BNNS@NWF using scratch coating and hot pressing processes. The composite film has a high TC of 6.42 W/mK at 45.8 wt% BNNS content, and has excellent insulation with a volume resistivity of 1.06 × 1015 Ω cm. This is due to the long‐range effective thermal conduction path constructed by BNNS, the bridging effect of Al2O3 and the synergistic effect of the two fillers. PDMS helps the composite film maintain good flexibility and good TC stability after 30 bending cycles. The PET nonwoven interlayer gives the composite film good mechanical properties with a tensile strength of 17.5 MPa. This work provides a strategy for the efficient preparation of flexible composite films with high TC and insulation properties, which is of great importance for the development of innovative thermal interface materials. Highlights: A sandwich‐structured composite film was prepared by a simple scale‐up method.Al2O3 and BNNS achieves synergistic enhancement of thermal conductivity.The film has a high thermal conductivity of 6.42 W/mK and electrical insulation.The film shows good flexibility, high tensile and thermal management properties. [ABSTRACT FROM AUTHOR]

In the realm of thermal interface materials (TIMs), high thermal conductivity and low density are key for effective thermal management and are particularly vital due to the growing compactness and lightweight nature of electronic devices. Efficient directional arrangement is a key control strategy to significantly improve thermal conductivity and comprehensive properties of thermal interface materials. In the present work, drawing inspiration from natural leaf and branch structures, a simple-to-implement approach for fabricating oriented thermal conductivity composites is introduced. Utilizing carbon fibers (CFs), known for their ultra-high thermal conductivity, as branches, this design ensures robust thermal conduction channels. Concurrently, boron nitride (BN) platelets, characterized by their substantial in-plane thermal conductivity, act as leaves. These components not only support the branches but also serve as junctions in the thermal conduction network. Remarkably, the composite achieves a thermal conductivity of 11.08 W/(m·K) with just an 11.1 wt% CF content and a 1.86 g/cm3 density. This study expands the methodologies for achieving highly oriented configurations of fibrous and flake materials, which provides a new design idea for preparing high-thermal conductivity and low-density thermal interface materials.

This work investigates a composite prepared with polyester and hexagonal boron nitride (hBN) in terms of the properties required in the material for microelectronics applications. The influence of filler loading and the surface treatment of hBN with a silane coupling agent (γ‐aminopropyl triethoxy silane) is studied. It has been observed that the silane‐modified hBN improves the compatibility and adhesion with the matrix as verified by SEM images. The experimental investigation reveals that the addition of hBN in polyester unwillingly rises the density, voids content, and water absorption rate. Though, the increment is limited with surface‐modified hBN. The material's mechanical properties improve with filler loading over a particular range of filler loading. The material's thermal conductivity and glass transition temperature increase with hBN content, whereas the coefficient of thermal expansion reduces. Polyester when filled with 40 wt% of the silane‐hBN, the thermal conductivity improves around six times that of unfilled polyester. The dielectric properties are marginally augmented with filler loading whereas, the increase in frequency results in the reduction of dielectric properties. It can be observed from the overall experimental analysis that the developed material can be used in different microelectronic applications. Highlights: A new class of composite is developed with polyester and raw/modified hBN.Composite with modified hBN shows improved physical/mechanical properties.Thermal properties of polyester improved appreciably with treated hBN.The dielectric properties of composites remain well within the range.The fabricated composites are recommended for microelectronics applications. [ABSTRACT FROM AUTHOR]

Boron nitride nano-platelets have been functionalized with oleylamine using a simple method without ultrasonication. The functionalization is effective with the formation of a coordination bonds between the boron nitride nano-platelets and the oleylamine molecules. The oleylamine functionalization allows for the production of 25% by weight loaded polyamide 6 – boron nitride composites having higher mechanical properties (15% tensile strength increase) and better through-plane thermal conductivity (0.85 to 0.99 W/m·K) with respect to the untreated samples. A better particle-matrix interaction is confirmed by SEM imaging and rheological analysis. The injection moulding process determines a filler orientation which influences the thermal conductivity. Graphical Abstract [ABSTRACT FROM AUTHOR]

It is well known that carbon fiber (CF) reinforced PEEK (polyether‐ether‐ketone) (defined as "PEEK/CF") composites have excellent properties and have been widely used in diverse fields. Meanwhile, hexagonal boron nitride (h‐BN), as an excellent nano reinforcing agent, is often incorporated into polymer to improve its mechanical strength and thermal conductivity. Herein, PEEK matrix was regulated by adding high‐strength CF as the load‐bearing phase and 2D h‐BN sheets as the solid lubricant and thermally conductive fillers prepared by melt blending to achieve the multi‐scale packing of uniform mixing. The results show that h‐BN is well dispersed in PEEK matrix and improves the interfacial bonding between CF and PEEK matrix, exhibiting a good synergistic effect in enhancing tensile properties of composites. PEEK composite with 20 wt% CF and 4 wt% h‐BN (referred as P/20C/4B) exhibits the highest tensile strength (176.05 MPa) and thermal conductivity (0.396 W/(m·K)), which are 97.54% and 126.3% over those of pure PEEK (89.12 MPa; 0.175 W/(m·K)), respectively. In addition, PEEK composite with 10 wt% CF and 4 wt% h‐BN (referred as P/10C/4B) has excellent tribological properties with a friction coefficient of 0.15, the lowest fiction temperature (30.5°C) and a relative low wear rate of 1.62 × 10−6 mm3/(N·m) among them. The synergitic effects of h‐BN and CF on mechanical, tribological properties and thermal conductivity of PEEK composites provides a very broad prospect in their application of low frictional and wear resistant polymeric materials. [ABSTRACT FROM AUTHOR]

In the present paper, we report polymer composites based on phenolic resin filled with hexagonal boron nitride; hot compression molding coupled with solution-based mixing were used to manufacture the composites. The paper presents experimental results on the physical and physicochemical properties of the obtained composites: thermal stability in air and argon, dielectric constant and dielectric loss tangent, active electrical resistance, thermal conductivity (mean and anisotropy), and mechanical strength. It is shown that the proposed technique of composite manufacturing, including the application of high-process pressures, makes it possible to obtain materials with high anisotropy of thermal conductivity, extremely high-filler content, and excellent dielectric properties, all of which are very important for prospective highly efficient lightweight heatsink elements for electronic devices. Experimental values of thermal conductivity and dielectric constant were analyzed using known mathematical models. Experimental values for thermal conductivities (up to 18.5 W·m−1·K−1) of composites at filler loadings of 65–85 vol.% are significantly higher than published data for bulk boron nitride/polymer composites. [ABSTRACT FROM AUTHOR]

With the rapid development of electronic devices and rubber tires, the industry has put forward new requirements for the heat dissipation of rubber components. With excellent thermal conductivity, oxidation resistance, and thermal stability, hexagonal boron nitride (h-BN) is often added to plastics or rubber as a thermally conductive filler, but is less effective when used directly. In this study, h-BN-K was prepared by direct modification of the mixed solution of KH-550, and KH-570, while h-BN-PK was prepared by co-modification of dopamine, KH-550, and KH-570. Two modified h-BN were added to natural rubber (NR) to improve the vulcanization properties, mechanical properties, and thermal conductivity. It was found that the tensile strength and thermal conductivity of 20 wt% h-BN-PK/NR composites were 30.6 MPa and 0.335 W/mK, which were 39.1% and 110.7% higher compared to pure NR (22.0 MPa and 0.159 W/mK), respectively. In addition, the addition of h-BN improved the thermal stability performance of NR to some extent. In conclusion, the h-BN-PK/NR composites provide a certain reference for the use of thermally conductive NR and suggest new ideas for heat dissipation of electronic devices. [ABSTRACT FROM AUTHOR]

Boron nitride nanosheet (BNNS) and graphene oxide (GO) as a single filler can effectively improve the thermal conductivity of the composites, and the synergistic mechanism of BNNS and GO was investigated in this paper. In this study, BNNS was first surface-functionalized and the multi-sized (50 nm, 200 nm, 500 nm) modified BNNS (A-BN) were attached to GO through non-covalent bonding interactions to form a cross-linked structure. Then, A-BN and GO were used as thermal fillers and support material adsorption eutectic phase change materials (PCMs) to prepare composite phase change material (CPCM). Characterization results show that small-size A-BN was more likely to form dense thermal networks with good compatibility and interface connectivity between PCMs, A-BN, and GO, ensuring that PCMs can be stored in the network without leaking. When the size of the BNNS was greater than 200 nm, the advantage of thermal conductivity obtained by A-BN was no longer obvious, and the phase change behavior of CPCM was inhibited. In general, the prepared CPCM has the ideal thermal response and thermal stability, which is very suitable for energy storage and thermal management applications. [ABSTRACT FROM AUTHOR]

In this article the structural, mechanical and thermal properties are investigated under pressures and temperatures by the first-principles calculations. The obtained results indicate that the value of V/V0 under different pressures slowly increases with the increase of temperature. The elastic modulus including bulk modulus, Shear modulus and Young's modulus of Li3BN2 increases with the increase of pressure. And pressure can improve the ductility and plasticity of Li3BN2. The vibrational free energy and enthalpy also increase with the increase of pressure, while the entropy and heat capacity gradually decrease with the increase of pressure. [ABSTRACT FROM AUTHOR]

To make the current charging time of electric vehicles meet the technical requirements of rapid charging, the higher the charging current needs to be increased. Consequently, higher requirements are put forward for the heat dissipation capacity of the charging pile cable. Therefore, obtaining insulation materials with good electrical and thermal properties is vital to solving the heat dissipation problem of charging pile cables. This paper modified polypropylene (PP) with polystyrene‐ethylene‐butadiene‐styrene (SEBS). Boron nitride nanosheets (BNNS) and boron nitride nanospheres (BNNOS) were used as thermally conductive fillers to construct A‐B‐A‐B ... A type thermally conductive pathways in SEBS/PP matrix. In SEM tests, it can be observed that the orientation of BNNS along the direction perpendicular to the pressure increases. DSC tests show that the introduction of BN particles lowers the melting point of the SEBS/PP matrix and increases the crystallization temperature of the composite. In the thermal conductivity experiment, with the rise of the content of BNNOS and the number of multilayer structures, the thermal conductivity gradually increases, up to 0.514 W/m K, which is three times the thermal conductivity of the SEBS/PP matrix. The tensile strength and elongation at the break of the composites decrease but the change of conductivity is not obvious. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials have sparked intense interest among the scientific community owing to their extraordinary mechanical, optical, electronic, and thermal properties. In particular, the outstanding electronic and optical properties of 2D materials make them show great application potential in high-performance photodetectors (PDs), which can be applied in many fields such as high-frequency communication, novel biomedical imaging, national security, and so on. Here, the recent research progress of PDs based on 2D materials including graphene, transition metal carbides, transition-metal dichalcogenides, black phosphorus, and hexagonal boron nitride is comprehensively and systematically reviewed. First, the primary detection mechanism of 2D material-based PDs is introduced. Second, the structure and optical properties of 2D materials, as well as their applications in PDs, are heavily discussed. Finally, the opportunities and challenges of 2D material-based PDs are summarized and prospected. This review will provide a reference for the further application of 2D crystal-based PDs. [ABSTRACT FROM AUTHOR]

The dependences between thermal conductivity and the maximum volume fraction of the filler in heat sink compound on the size, morphology, specific surface area, and particle porosity, as well as the contact angle with silicone, of various materials such as aluminum oxides, silicon, magnesium, aluminum and boron nitrides, silicon carbide, metals (aluminum, copper, nickel), and carbon materials (graphite and diamond) is presented. The quality of the produced heat sink compound is not governed by any single property listed, but rather by the combination of properties such as morphology and specific surface area (or porosity) of the particles. For each type of filler particle shape, an inversely proportional relationship exists between the specific surface area and the maximum volume fraction of the polymer. Specific aspects were discussed regarding the effect of the material's phase and chemical composition on the angle of wettability by polydimethylsiloxane. [ABSTRACT FROM AUTHOR]

Combining thermal conductivity with electrical isolation is a very interesting topic for electronic applications in order to transfer the generated heat. Typical approaches combine thermally conductive fillers with a thermoplastic matrix. The aim of this work was to investigate the influence of different fillers and matrices on the thermal conductivity of the polymer matrix composites. In this study, various inorganic fillers, including aluminum oxide (Al2O3), zinc oxide (ZnO), and boron nitride (BN) with different shapes and sizes, were used in matrix polymers, such as polyamide 6 (PA6), polypropylene (PP), polycarbonate (PC), thermoplastic polyurethane (TPU), and polysulfone (PSU), to produce thermally conductive polymer matrix composites by compounding and injection molding. Using simple mathematical models (e.g., Agari model, Lewis–Nielson model), a first attempt was made to predict thermal conductivity from constituent properties. The materials were characterized by tensile testing, density measurement, and thermal conductivity measurement. Contact angle measurements and the calculated surface energy can be used to evaluate the wetting behavior, which correlates directly with the elastic modulus. Based on the aforementioned evaluations, we found that besides the volume fraction, the particle shape in combination with the intrinsic thermal conductivity of the filler has the greatest influence on the thermal conductivity of the composite. [ABSTRACT FROM AUTHOR]

This work studies the effects of graphene nanoplatelets (GNPs) and hexagonal boron nitride (hBN) on the thermal and mechanical properties of polydimethylsiloxane (PDMS) matrix for use as thermal interface materials (TIMs). Solution mixing of 10 wt% GNPs and 40 wt% hBN with PDMS produced TIMs with through-plane thermal conductivity (TC) of 1.24 W m−1 K−1 showing a 519% increase relative to the neat matrix. A synergistic effect between GNPs and hBN was particularly demonstrated when in samples with 48 wt% total filler content, 8 wt% hBN was replaced by GNPs, and the TC was increased by 33%. The elongation at break of the hBN (40 wt%)/GNP (8 wt%) samples reached 151%, representing a 160% increase when compared to samples with only 40 wt% hBN. Moreover, the shore hardness of samples containing 40 wt% hBN was 68 A, and the introduction of 8 wt% GNPs caused a decrease to 38 A. DSC measurements on samples filled with hBN and GNPs showed a reduction up to 65% in Ultimate Heat of Curing, which was attributed to the presence of graphene flakes interfering with the curing of the matrix. Graphene was found to be an efficient filler in tuning the thermal and mechanical properties of TIMs. [ABSTRACT FROM AUTHOR]

The intrinsic thermal conductivity coefficient of polyarylene ether nitrile (PEN) is low, which brings difficulty in meeting the need of advanced electronic equipment and microelectronic integrated circuit. In this research, h‐BN was mixed into PEN as fillers in view of its remarkable thermal conductivity and electrical insulation, and the influence of filler content on properties in many aspects was studied in depth. The microcosmic arrangement and interfacial compatibility between fillers and matrix were studied by SEM. AR, DSC, TGA and hot‐disk methods were performed to analyze thermal property. The results confirmed that thermal conductivity of composites was increased to 0.5444 Wm−1 K−1 at 30 wt% filler content, having 22.89% increment compared with PEN copolymer without addictive. Moreover, this PEN/h‐BN composite shows excellent thermal properties with Tg of 214.83°C, and T5% of 535.09°C. Furthermore, the dielectric constant and insulation performance of composite with 30 wt% h‐BN are improved, while the dielectric loss is kept low of 0.02 at 1 kHz. The tensile strength is 62.3 MPa and elastic modulus is 3567.5 MPa. In a whole, the 30 wt% h‐BN/PEN composite prepared in this work exhibit great potentiality and promising prospect in the field of electronics. [ABSTRACT FROM AUTHOR]

Aiming at developing insulating materials with high thermal conductivity (TC), which can make up for the shortcoming that graphene cannot be used directly in electronic devices because of its zero band gap, we systematically study the thermal transport of the hexagonal boron nitride nanoribbons (BNNRs) composed of one multilayer central region (CR) and two monolayer regions (MRs). We show that the TC and the interfacial thermal conductivity (ITC) depend on the BNNR structure parameters and the temperature in different ways. As the CR layer number increases the ITC will decrease, indicating the two-layer BNNR will show the largest ITC. The TC will increase and the ITC will fluctuate around a certain value with increasing the MR length. However, with the increase of the BNNR width, both TC and ITC will show oscillations near certain values. Furthermore, we find that the ITC (TC) will increase (decrease) with the temperature increasing. Finally, we calculate the ITC of the compound BNNRs in different stacking manners and find the ITC for the AB stacking is greater than that for the AA stacking. This research presents the possible measures for manipulating heat transport and demonstrates that the whole heat transport performance is fundamentally determined by the interfaces. [ABSTRACT FROM AUTHOR]

The efficiency of electronic microchip-based devices increases with advancements in technology, while their size decreases. This miniaturization leads to significant overheating of various electronic components, such as power transistors, processors, and power diodes, leading to a reduction in their lifespan and reliability. To address this issue, researchers are exploring the use of materials that offer efficient heat dissipation. One promising material is a polymer–boron nitride composite. This paper focuses on 3D printing using digital light processing of a model of a composite radiator with different boron nitride fillings. The measured absolute values of the thermal conductivity of such a composite in the temperature range of 3–300 K strongly depend on the concentration of boron nitride. Filling the photopolymer with boron nitride leads to a change in the behavior of the volt–current curves, which may be associated with the occurrence of percolation currents during the deposition of boron nitride. The ab initio calculations show the behavior and spatial orientation of BN flakes under the influence of an external electric field at the atomic level. These results demonstrate the potential use of photopolymer-based composite materials filled with boron nitride, which are manufactured using additive techniques, in modern electronics. [ABSTRACT FROM AUTHOR]

The effect of three types of nanofillers on the physical, mechanical, and thermal properties of flexible polyurethane foams (FPUF) was studied. FPUF with nanofillers are of interest to the automotive industry due to their potential for enhancing compression properties and enabling sustainable foams. Holey and wrinkled flash graphene, and untreated and silane coated boron nitride were tested as fillers up to 0.1 wt% loading level. Flash graphene filled FPUF showed significant improvement in compressive properties, especially at the 0.025 wt% loading level, showing a 22% increase in compressive force deflection at 25% strain and a 17% increase at 50% strain compared to the unfilled control foam sample. Boron nitride nanoparticles, treated and untreated, were shown to be an effective means of reducing wet compression set properties, addressing a key area of concern for sustainable polyols. Wet compression set was reduced by 20%–30% for most boron nitride foams compared to their unfilled control samples. Boron nitride may enable implementation of more sustainable polyols in automotive FPUF. Nanofillers did not significantly improve thermal stability of FPUF. [ABSTRACT FROM AUTHOR]

A composite was prepared by in‐situ polymerization of liquid crystal epoxy (LCE4) with a low dielectric and high thermal conductivity boron nitride (BN) filler, which the filler (f‐BN) was surface‐functionalized by γ‐glycidoxypropyltrimethoxysilane (KH560) and aminopropylisobutyl polyhedral oligomeric silsesquioxane (NH2‐POSS). The surface‐functionalized BN was more uniformly dispersed in LCE4, which improved the interfacial compatibility between inorganic and organic phases. Compared with pure LCE4, KH560, and NH2‐POSS modified f‐BN/LCE4 composites exhibited a higher glass transition temperature, better thermal stability, and higher thermal conductivity. For example, when the f‐BN content reached 30 wt%, the energy storage modulus of the composite increased to 2580 MPa, and the glass transition temperature was 103°C. The thermal conductivity of this 30 wt% f‐BN composite was 0.48 W m−1 K−1, 128.6% higher than that of pure LCE4. In addition, thermal stability, low hygroscopicity, and dielectric properties of the composites were characterized and analyzed to explore the application prospects of f‐BN/LCE4 composites in electronic packaging and in high‐performance microelectronic devices. [ABSTRACT FROM AUTHOR]

Polyimide (PI) composite films with hybrid fillers containing hBN (hexagonal boron nitride) sheets and rGO (reduced graphene oxide) were successfully fabricated by in‐situ polymerization. Herein, hBN sheets and rGO were obtained by ball milling and chemical reduction, respectively. In PI composite films, hBN can be tightly attached onto the surface of rGO via π‐π interaction, which can benefit the construction of heat‐conduction pathways and reduce boundary of heat resistance. The results show that the addition of rGO and hBN could enhance the thermal conductivity by synergistic effects. Specially, hBN and rGO are at the weight ratio of 1:1 and at the total loading of 33 wt%, thermal conductivity of PI composites can reach up to 1.19 Wm−1 K−1, which is 5.61 times higher than that of pure PI. Thermal property and dynamic mechanical property of composite films were also investigated. Besides, compared with pure PI, mixed fillers have obvious surface‐enhanced Raman scattering signals, indicating the synergistic effect of the mixed fillers. Overall, this study gives insights into heat dissipative and high sensitivity analysis components which may be used in the field of high‐temperature micro fabrication. [ABSTRACT FROM AUTHOR]

Hexagonal boron nitride nanosheets (BNNS) and their photosensitive resin-based composites have excellent thermal conductivity, thermal stability, and electrical properties, making them promising applications in electronic devices and packaging. In this paper, BNNS were exfoliated by hydrothermal method, and BNNS/photosensitive resin composite was prepared by ultraviolet curing. The enhancement effect of BNNS on the thermal stability and electrical properties of the composites was studied. The result showed that few-layer BNNS with hexagonal structure were obtained after hydrothermal exfoliation of hexagonal boron nitride (h-BN), part of the B–N bond in BNNS formed a covalent bond with the photosensitive resin matrix. Both of chemical interface and overlapping interface formed between BNNS and the matrix help to form a better and tighter interface, which effectively improves the thermal stability of the photosensitive resin. As the mass percentage of BNNS increases, the temperature required for the decomposition of BNNS/photosensitive resin composites increases, and the relative permittivity also increases significantly because of the interface polarization. When the content of BNNS reaches 10 wt%, it reaches the highest value of 7.623 at the frequency of 1 kHz. Due to the high surface area of the few-layer BNNS, a network structure is formed in the matrix, which improves the breakdown strength of the photosensitive resin. [ABSTRACT FROM AUTHOR]

Due to the rapid development of multifunctional and miniaturized electronic devices, the demand for polymer composites with mechanical properties, high‐thermal conductivity, and dielectric properties is increasing. Therefore, the heat dissipation capacity of the composite must be improved. To solve this problem, we report a glass fabric (GF)/boron nitride (BN) network with a highly thermally conductive hetero‐structured formed using polyvinyl alcohol (PVA) as an adhesive. The GF and BN are furtherly modified by (3‐aminopropyl)triethoxysilane (APTES) for better thermal conductivity enhancement. When the BN content is 30%, the thermal diffusion coefficient and thermal conductivity of obtained PVA‐mBN@mGF (PBG) are 2.843 mm2/s and 1.394 W/(m K), respectively. Epoxy (EP) resin is then introduced to prepare PBG/mBN/EP laminated composites via the hot pressing method as applied as thermal conductive composites. A highest thermal conductivity of 0.67 W/(m K) of PBG/mBN/EP laminated composites is obtained, three times higher than that of pure EP. In addition, the PBG/mBN/EP laminated composites also present favorable mechanical, electrically insulating, and dielectric properties. [ABSTRACT FROM AUTHOR]

Thermal conductivity (TC) and thermal stability are the basic requirements and highly desirable properties in thermal management, heat storage and heat transfer applications. This work is regarding the fabrication of polystyrene/boron nitride composites and melt extruded to produce good thermal stability, increased thermal conductivity and enhanced mechanical properties. Our strategy is potentially applicable to produce thermally conductive composites of low cost over large scale. Boron nitride powder is bath sonicated in 10% NH3 solution to avoid its agglomeration and tendency toward entanglement in a polymer matrix. An approximately 67.43% increase in thermal conductivity and 69.37% increase in tensile strength as well as 56 multiple increases in thermal stability of the optimum samples were achieved. The developed polymeric composites are potentially applicable in the electronic industry, especially in electronic devices used for 5G, heat sink and several other aviation applications. [ABSTRACT FROM AUTHOR]

To improve the thermal conductivity of balsa wood, infiltrating boron nitride (BN) and epoxy (EP) resin into the wood after delignification treatment was shown to be a feasible strategy. Scanning electron microscopy, energy-dispersive x-ray spectroscopy, Fourier transform infrared analysis, and x-ray diffraction analysis were used to verify the successful dispersion and immobilization of BN and EP in the wood. The effect of the ratio of BN to EP on the thermal properties was subsequently examined. The thermal conductivity of the BN/EP composite increased with higher BN content in the EP resin. For a BN-to-resin weight ratio of 1:70, the thermal conductivity reached a maximum of 0.388 W m−1 K−1, representing a 605% increase compared to natural balsa wood. The thermal conductivity decreased for higher ratios. Using a BN–EP ratio of 1:70, nine BN/EP composites were impregnated, superimposed, and cured together. The measured thermal conductivity was 0.473 W m−1 K−1. The performance of the BN/EP composites as a light-emitting diode (LED) heat dissipation substrate was evaluated using numerical simulation and infrared imaging. The sample exhibited excellent thermal conductivity performance, providing a potential avenue for preparing LED heat dissipation substrates. [ABSTRACT FROM AUTHOR]