Epoxy Composites with High Thermal Conductivity by Constructing Three-Dimensional Carbon Fiber/Carbon/Nickel Networks Using an Electroplating Method

A Through-Thickness Arrayed Carbon Fibers Elastomer with Horizontal Segregated Magnetic Network for Highly Efficient Thermal Management and Electromagnetic Wave Absorption

Multifunctional thermal management materials with highly efficient electromagnetic wave (EMW) absorption performance are urgently required to tackle the heat dissipation and electromagnetic interference issues of high integrated electronics. However, the high thermal conductivity (λ) and outstanding EMW absorption performance are often incompatible with each other in a single material. Herein, a through-thickness arrayed NiCo₂ O₄ /graphene oxide/carbon fibers (NiCO@CFs) elastomer with integrated functionalities of high thermal conductivity, highly efficient EMW absorption, and excellent compressibility is reported. The NiCO@CFs elastomer realizes a high out-of-plane thermal conductivity of 15.55 W m^-1  K^-1 , due to the through-thickness vertically aligned CFs framework. Moreover, the unique horizontal segregated magnetic network effectively reduces the electrical contact between the CFs, which significantly enhances impedance matching of NiCO@CFs elastomer. As a result, the vertically arrayed NiCO@CFs elastomer synchronously exhibits ultrabroad effective absorption bandwidth of 8.25 GHz (9.75-18 GHz) at a thickness of 2.4 mm, good impedance matching, and a minimum reflection loss (RL_min ) of -55.15 dB. Given these outstanding findings, the multifunctional arrayed NiCO@CFs elastomer opens an avenue for applications in EMW absorption and thermal management. This strategy of constructing thermal/electrical/mechanical pathways provides a promising way for the high-performance multifunctional materials in electronic devices.

Carbon Fabric Decorated with In-Situ Grown Silver Nanoparticles in Epoxy Composite for Enhanced Performance

The current study focuses on studying the effect of reinforcement of carbon fabric (CF) decorated with in-situ grown silver (Ag) nanoparticles (NPs) on the performance properties of epoxy composite. The Ag NPs were grown on carbon fabric by reducing silver nitrate. The main objective of developing such an innovative reinforcement was to improve thermal conductivity, interlaminar strength, and tribological properties of CF-epoxy composites. The growth of NPs on the surface of CF was confirmed through scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDAS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction studies. The development of composites was conducted by the impregnation method, followed by compression molding. It was observed that in-situ growth of Ag NPs enhanced thermal conductivity by 40%, enhanced inter-laminar shear strength by 70%, enhanced wear resistance by 95%, and reduced the friction coefficient by 35% in comparison to untreated CF.

Development and Perspectives of Thermal Conductive Polymer Composites

With the development of electronic appliances and electronic equipment towards miniaturization, lightweight and high-power density, the heat generated and accumulated by devices during high-speed operation seriously reduces the working efficiency and service life of the equipment. The key to solving this problem is to develop high-performance thermal management materials and improve the heat dissipation efficiency of the equipment. This paper mainly summarizes the research progress of polymer composites with high thermal conductivity and electrical insulation, including the thermal conductivity mechanism of composites, the factors affecting the thermal conductivity of composites, and the research status of thermally conductive and electrical insulation polymer composites in recent years. Finally, we look forward to the research focus and urgent problems that should be addressed of high-performance thermal conductive composites, which will provide strategies for further development and application of advanced thermal and electrical insulation composites.

An Efficient Method to Determine the Thermal Behavior of Composite Material with Loading High Thermal Conductivity Fillers

Improvement of the thermal conductivity of encapsulant material using doping filler is an important requirement for electronic device packaging. We proposed a simple method for determining the thermal characteristics of composite material that can help save time, increase research performance, and reduce the cost of buying testing equipment. Based on the theory of Fourier law, a general 3D model is simplified into a 2D model, which can then be applied to calculate the thermal conductivity of the tested sample. The temperature distribution inside the sample is simulated by the finite element method using MATLAB software; this is a simple and useful option for researchers who conduct studies on thermal conduction. In addition, an experimental setup is proposed to help determine the extent of thermal conductivity improvement in a sample with doping filler compared to a bare sample. This method is helpful for research on optoelectronics packaging, which relates to the enhancement of thermal conductivity composite material.

Polymer-Assisted Dispersion of Boron Nitride/Graphene in a Thermoplastic Polyurethane Hybrid for Cooled Smart Clothes

The avoidance and mitigation of energy wastage have attracted increasing attention in the context of global warming and climate change. With advances in materials science, diverse multifunctional materials with high thermal conductivity have shown excellent energy-saving potential. In this study, a hybrid film exhibiting high thermal conductivity with excellent stretchability and washability was prepared. First, a simple surface modification of boron nitride (BN) was performed to realize a modified boron nitride (BNOH) filler. Next, an organic dispersant was synthesized to enhance the dispersion of BNOH and graphene nanoplatelets (GNPs) in the proposed composite. Subsequently, a simple procedure was used to combine the dispersed GNPs and BNOH fillers with thermoplastic polyurethane (TPU) to fabricate a hybrid structure. The hybrid films composed of BNOH-GNP/TPU with a dispersant exhibited a high thermal conductivity of 12.62 W m^-1 K^-1 at a low filler loading of 20 wt.%. This hybrid film afforded excellent stretchability and washability, as indicated by the very small thermal-conductivity reduction to only 12.23 W m^-1 K^-1 after 100 cycles of fatigue testing and to 12.01 W m^-1 K^-1 after 10 washing cycles. Furthermore, the cooling and hydrophobicity properties of the hybrid film were enhanced when compared with neat TPU. Overall, our approach demonstrates a simple and novel strategy to break the passive effect of traditional commercial cooling clothing by combining a high-thermal-conductivity film with an active cooling source to amplify the cooling effect and develop wearable cooled smart clothes with great commercial potential.