Enhanced Thermal Conductivity of Epoxy Composites by Introducing 1D AlN Whiskers and Constructing Directionally Aligned 3D AlN Filler Skeletons

Abstract

With the miniaturization of current electronic products, ceramic/polymer composites with excellent thermal conductivity have attracted increasing attention. For regular ceramic particles as fillers, it is necessary to achieve the highest filling fraction to obtain high thermal conductivity, yet leading to higher production cost and reduced mechanical properties. In this paper, AlN whiskers with a high aspect ratio were successfully prepared using a modified direct nitriding method, which was further paired with AlN particles as fillers to prepare the AlN/ epoxy composites. It is indicated that AlN whiskers could form bridging links between AlN particles, which favored the establishment of thermal pathways inside the polymer matrix. On this basis, we constructed the 3D AlN skeletons as a thermal conductivity pathway by the freeze-casting method, which could further enhance the thermal conductivity of the composites. The synergistic enhancement effect of 1D AlN whiskers and directional filler skeletons on the composite thermal conductivity was further demonstrated by the actual heat transfer process and finite element simulations. More significantly, the experimental results showed that the addition of one-dimensional fillers could also effectively improve the thermal stability and mechanical properties of the composites, which was beneficial for preparing high-performance TIMs.

Enhanced In-Plane Thermal Conductivity and Mechanical Strength of Flexible Films by Aligning and Interconnecting Si3N4 Nanowires

“…It will not only deteriorate the mechanical properties of the composite but also severely increase the cost. Therefore, the rational design of the thermal conductive network structure using low-dimensional fillers to obtain relatively higher thermal conductivity at a lower filling fraction has become a hot research concern . In recent years, a variety of low-dimensional fillers have been reported, such as silicon carbide (SiC) nanowires, carbon fibers (CFs), graphene oxide (GO), − carbon nanotubes (CNTs), Ag nanowires, and boron nitride nanosheets (BNNs). − Among the reported low-dimensional fillers, carbon and metallic materials not only have very high thermal conductivity but also exhibit high electrical conductivity, which is not suitable for applications with high insulation requirements.…”

Facile and Scalable Strategy for Fabricating Highly Thermally Conductive Epoxy Composites Utilizing 3D Graphitic Carbon Nitride Nanosheet Skeleton

“…Along with the miniaturization trend of electronic devices toward high integration and power density, the problem of heat accumulation is becoming prominent, which may greatly impair the performance, efficiency, and reliability of electronic devices. , High-performance thermal interface materials (TIMs) are commonly applied to accelerate the dissipation of concentrated heat for keeping electronic devices cool. , Epoxy resins are widely used in various electronic devices, including electromagnetic materials, dielectric materials, and thermally conductive materials. − Epoxy-based TIMs are popular materials for electronic packaging and thermal management application because of their attractive electrical insulation, thermal stability, mechanical strength, and easy processability. However, limited by the inferior thermal conductivity of neat epoxy (∼0.2 W/m·K), the combination of thermally conductive fillers is usually employed to improve its thermally conductive performance. − …”

“…Constructing a three-dimensional (3D) thermally conductive network in a polymer matrix has been proven to be one of the most efficient strategies to enhance the heat transfer efficiency of TIMs. − By this way, a number of continuous heat transfer channels are created, allowing phonons to be transferred with minimal resistance. A plethora of efforts have been made to design and achieve a 3D thermally conductive network, such as freeze-drying, chemical vapor deposition, electrospinning, and hot-pressing . Although a significant thermally conductive enhancement has demonstrated in these studies, most of these preparation methods still possess some limitations, such as time consumption, complex operation process, and relatively harsh experimental conditions, which hinder their practical application on a large scale.…”

Thermal Conductivity Enhancement of Graphene/Epoxy Nanocomposites by Reducing Interfacial Thermal Resistance

“…It has been widely used as a thermal interface material due to its high bonding property, good electrical insulation, low cost, and other properties. 1−4 However, the intrinsic thermal conductivity (TC) of epoxy is low, 5,6 which does not meet the dissipation requirements for high heat flux components, such as chips. Graphene is a twodimensional material with a TC of 2000−5000 W m −1 K −1 .…”

“…Epoxy is a thermosetting resin crosslinked by an epoxy monomer and a curing agent. It has been widely used as a thermal interface material due to its high bonding property, good electrical insulation, low cost, and other properties. − However, the intrinsic thermal conductivity (TC) of epoxy is low, , which does not meet the dissipation requirements for high heat flux components, such as chips. Graphene is a two-dimensional material with a TC of 2000–5000 W m –1 K –1 . , As the thermally conductive filler, graphene has great potential for improving the TC of epoxy, and graphene/epoxy composites have been an intensive subject in recent years. − …”