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Highlights Increasing miniaturization and integration of microelectronic devices have led to an unprecedented attention on heat dissipation and signal transmission of electronic equipment. However, the mostly used method to enhance the thermal conductivity of polymers by adding thermally conductive fillers usually results in the increase of dielectric constant (Dk). It was still challenging to synergistically achieve low Dk and high thermal conductivity of polymer‐matrix composites. Herein, hydroxylated boron nitride nanosheet (BNNS‐OH) with a high yield of 35.67% was prepared by the liquid ultrasonic exfoliation under the assistance of sodium cholate (SC), and grafted with (1H,1H,2H,2H‐perfluorodecyl) trimethoxy silane to prepare fluorinated boron nitride nanosheets (F‐BNNS), which can uniformly disperse in liquid silicone rubber (LSR) and reduce the Dk of LSR composites. The thermal conductivity of LSR composites with 20 wt% F‐BNNS reached 0.489 W·m−1·K−1, showing an increase of 307.35% in comparison with pure LSR (0.12 W·m−1·K−1). Meantime, the Dk of as‐obtained LSR/F‐BNNS (20 wt%) composites is reduced from 3.4 to 2.6, and the dielectric loss (Df) is less than 0.012. The facile and rational design of fluorinated BNNS offers a new insight for the high‐end electronic packaging materials. A new method of exfoliation and fluorinated treatment of h‐BN was proposed. The LSR composites achieved an ultralow Dk of 2.63 via fluorinated BNNS. Thermal conductivity of LSR composites increased by 307.35% than pure LSR. [ABSTRACT FROM AUTHOR]

With the rapid growth of highly integrated electrical devices, the urgent demand for polymer composites with high thermal conductivity (TC) is increasing for effective thermal management. In this work, boron nitride nanosheets (BNNSs) were chemically grafted with aluminum oxide (Al2O3) to develop hetero‐structured filler (BNNSs@Al2O3). The BNNSs@Al2O3 fillers were uniformly dispersed in the poly(vinyl alcohol) (PVA) by solvent mixing, verified by SEM, and the oriented BNNSs@Al2O3/PVA composites were produced by the doctor blade method. The results exhibited that the synergistic effect of BNNSs and Al2O3 was achieved, and the thermal conductivities of BNNSs@Al2O3/PVA composites were improved. When keeping the filler content at 30 wt%, the in‐plane and out‐of‐plane TC of BNNSs@Al2O3/PVA composite reached 5.641 and 0.651 W/(m·K), respectively. The BNNSs@Al2O3 filler may improve the performance of composite heat dissipation by reducing the interfacial resistance between fillers and making it easier to establish directed heat‐transfer pathways. This composite demonstrates promising application in the field of electronic packaging. [ABSTRACT FROM AUTHOR]

The high demand for thermally conductive materials in the housing and packaging industry of electronic device highlights the necessity for the development of novel thermal conductivity materials. In this study, waste poplar wood was delignified and combined with boron nitride (hBN) to establish a blend system with a cross thermally conductive network. Using the vacuum‐assisted resin transfer molding process, a biobased composite material was prepared with high thermal conductivity (1.41 W m−1 K−1), mechanical strength (flexural strength of 100.7 MPa and tensile strength of 40.0 MPa), flame retardancy, and water resistance. Compared with raw wood, the incorporation of hBN increased the thermal conductivity of the prepared material by 1324.2%. The high thermal conductivity performance surpassed that of most polymers and elastomers commonly used in electronic component heat dissipation materials, indicating the enormous potential of the prepared composite material in the field of heat dissipation materials. [ABSTRACT FROM AUTHOR]

Enhancing the thermal conductivity of epoxy resin is an urgent demand for its application in electronic packaging field. In this work, thermally conductive epoxy/graphite composite featuring excellent self‐healing and reprocessability is prepared based on covalent adaptable networks. The effect of graphite on the rheology, reprocessing, and self‐healing properties of epoxy have been studied. The result shows that the prepared composites can be easily reprocessed and have excellent self‐healing property. On the fundamental of the highly multifunctional performance of the epoxy composites, highly thermally conductive bulk composites are constructed via multilayered stacking up and self‐healing based on the film composites, which is prepared using a rolling method. It is demonstrated that the films can assemble into new substance bulk by stacking up through self‐healing. The high thermal conductivity is achieved by the highly aligned graphite induced by the rolling process. Result reveals that, being filled with 50% mass fraction of GR, the bulk composites possesses high thermal conductivity of 8.411 Wm−1 K−1. This work provides a new strategy to prepare recyclable and highly thermally conductive epoxy. [ABSTRACT FROM AUTHOR]

In this work, a novel thermal conductive and electrical insulation composite paper fabricated through doctor‐blading followed by hot‐pressing was reported. Specifically, by loading silver nanoparticles (AgNPs) on the surface of boron nitride nanosheets (BNNS) and silicon carbide wires (SiCw), the BNNS and SiCw were bridged through the sintered AgNPs to form a heat conduction path. The results indicate that the prepared composite paper not only enhances the thermal conductivity to 47 W m−1 k−1 but also possesses good mechanical properties and high electrical insulation. The optimizations can be attributed to the efficient BNNS/Ag/SiCw networks within the paper and strong interfacial combination through sintered AgNPs. Furthermore, the distribution and size of the AgNPs also affect the properties of the composites. This work provides a promising strategy to improve thermal conductivity of the composites by constructing efficient thermal conductive pathways, which are suitable for large‐scale preparation and have potential to be widely used in the field of electronic packaging. [ABSTRACT FROM AUTHOR]

Novel polymer‐based materials with highly thermally conductive and high‐mechanical properties have attracted extensive attention in the field of electronic packaging as thermal interface materials (TIMs), due to the development of electronic equipment to miniaturization and higher power density. However, how to achieve high‐thermal conductivity (exceed 5 W/m·K) with low‐filling content (below 30 vol%) is still the focus of attention. Herein, polymer‐based materials with excellent in‐plane thermal conductivity were prepared by a simple hot‐pressing strategy, and a series of nanocomposites with different orientations were controlled by the hot‐pressing times. As expected, compared with that of randomly dispersed 25 vol% BNNS/P(VDF‐HFP) nanocomposite and pristine P(VDF‐HFP), the in‐plane thermal conductivity of oriented 25 vol% BNNS/P(VDF‐HFP) is promoted by 249% and 3057%, respectively. In contrast to randomly dispersed composites, oriented BNNS/P(VDF‐HFP) at loadings above 10 vol% begin to show an encouraging upward trend. This is because the orientation of BNNS can significantly reduce the percolation threshold and construct an efficient heat conduction network under low‐filling volume. Therefore, this technology can provide new ideas for the development of electronic packaging technology. [ABSTRACT FROM AUTHOR]

Polymers are known as thermally insulated materials with reported effective thermal conductivity (Keff) in the range of 0.1 to 0.5 Wm−1 K−1. However, increasing demand for smaller and more powerful electronics has created the need for thermally conductive polymers for use in heat exchangers and electronic packaging applications. Given this background, much research has been done over the past two decades to increase the Keff of polymers. Based on the strategy involved, those works can be divided into two main categories: (i) increasing the Keff of the neat polymer by aligning its chains orientation; and (ii) increasing polymer Keff by fabrication of polymeric composites with thermally conductive filler networks. Among these two strategies, the former is limited to nanoscale laboratory research and is difficult to scale up for mass production. Therefore, this work is mainly focused on the latter category, thermally conductive polymeric composites, which has a higher potential for large‐scale production. This work aims to summarize, evaluate, and highlight the successful strategies of the recent efforts in enhancing the thermal conductivity of polymer composites. The major achievements, future challenges, and the outlooks of high thermally conductive polymeric composites are presented by analyzing the results of about 300 works. [ABSTRACT FROM AUTHOR]