scholarly journals Hyperbolic graphene framework with optimum efficiency for conductive composites

2021 ◽  
Author(s):  
Xiaoting Liu ◽  
Kai Pang ◽  
Yingjun Liu ◽  
Chao Gao ◽  
Zhen Xu
Keyword(s):  
Thermal Management ◽  
Structural Design ◽  
Design Space ◽  
High Efficiency ◽  
Conductive Filler ◽  
Face To Face ◽  
Conductive Composites ◽  
Electrical Conductivities ◽  
Thermally Conductive ◽  
Multifunctional Nanocomposites

Abstract Constructing conductive filler networks with high efficiency is essential to fabricating functional polymer composites. Although two-dimensional (2D) sheets have prevailed in nanocomposites, their efficiency in enhancing conductive functions seems to reach the limit, as if merely addressing the dispersion homogeneity. Here, we exploit the unrecognized geometrical curvature of 2D sheets to break the efficiency limit of filler systems. The hyperbolic curvature meditates the incompatibility between 2D topology and 3D filler space and holds the efficient conductive path through face-to-face contact. The hyperbolic graphene framework exhibits the record efficiency in enhancing electrically and thermally conductive functions of nanocomposites. At volume loading of only 1.6%, the thermal and electrical conductivities reach 31.6 W/(mK) and 13,911 S/m, respectively. Nanocomposites with hyperbolic graphene framework exhibit great potentials in thermal management, sensing and electromagnetic shielding. Our work presents a geometrically optimal filler system to break the efficiency limit of multifunctional nanocomposites and broadens the structural design space of 2D sheets by curvature modulation to meet more applications.

scholarly journals Measurements of Aluminum-Annealed Pyrolytic Graphite Composite Baseplates with Improved Thermal Conductivity

2021 ◽  
Vol 16 (2) ◽  
pp. 042-047
Author(s):  
Yanfei Bian ◽  
SHI Jian-zhou ◽  
XIE Ming-jun ◽  
CAI Meng
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Management ◽  
Pure Aluminum ◽  
Pyrolytic Graphite ◽  
Aluminum Plate ◽  
Graphite Composite ◽  
Conductive Composites ◽  
Thermal Potential ◽  
Thermally Conductive

Annealed pyrolytic graphite (APG) is a material with thermal conductivity of about 1500 W/(m·K). This property may enable the usage of APG’s thermal potential to develop highly thermally conductive composites for devices requiring effective thermal management. In this paper, APG has been encapsulated in aluminum by brazing, and the thermal properties of Al-APG composite baseplates were measured. The results show that the thermal conductivity of the Al-APG composite baseplates is about 620 W/(m·K), which is four times higher than the pure aluminum plate (152 W/(m·K)).

Insulating and Thermally Conductive Composite Filled with Boron Nitride Particles

2011 ◽  
Vol 391-392 ◽  
pp. 282-286 ◽  
Author(s):  
Jun Peng Li ◽  
Shu Hua Qi ◽  
Fan Xie
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stability ◽  
Boron Nitride ◽  
Filler Content ◽  
Glass Fibers ◽  
High Surface ◽  
Conductive Filler ◽  
Volume Resistivity ◽  
Conductive Composites ◽  
Thermally Conductive

A new kind of thermally conductive composites reinforced by glass fibers with boron nitride (BN) as thermally conductive filler was prepared in heat press molding. Thermal conductivity of the composites was found to increase with increasing in filler content. But impact strength and flexural strength reach the top point, 385.05KJ/m2 and 912.6481MPa, with content of 50wt% and 20wt% respectively. The thermal conductivity of 0.8385 W/mK was obtained at 50wt% filler content. Experimental dates show that mixed matrix of epoxy (EP) and polyimide (PI) displays high thermal stability and can improve thermal stability compared to pure epoxy obviously at 50wt% PI content. Additionally, the obtained composites possess high surface resistivity and volume resistivity, which are suitable for substrate materials.

scholarly journals Preparation of Binary Thermal Silicone Grease and Its Application in Battery Thermal Management

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4763
Author(s):  
Ziqiang Liu ◽  
Juhua Huang ◽  
Ming Cao ◽  
Guiwen Jiang ◽  
Jin Hu ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Thermal Management ◽  
Heat Dissipation ◽  
Silicone Oil ◽  
Conductive Filler ◽  
Methyl Silicone ◽  
Battery Thermal Management ◽  
Thermally Conductive ◽  
Change Material

To improve the problems of large interface thermal resistance and low heat dissipation efficiency in battery thermal management (BTM), this paper uses methyl silicone oil as the matrix, AIN, copper powder (CP), and carbon fiber (CF) as thermally conductive fillers, and acetone and stearic acid as particle surface modification components. A variety of binary thermal silicone greases (TSGs) with different compositions were prepared. Different instruments were used to test the material properties of TSGs, and a better TSG was selected to coat the interface between battery and phase change material (PCM) for battery charging and discharging experiments. Through the analysis of experimental data, it was found that among the TSGs made of three mixed fillers (AIN/CP, AIN/CF, CP/CF), the three TSGs had good thermal stability, and their thermal degradation temperature both exceeded 300 °C. As the ratio of thermally conductive filler was gradually changed from 5:1 to 1:5, the TSG containing CP/CF had higher thermal conductivity and lower volume resistivity, while the TSG containing AIN/CF had the least damage due to interface wear. The acidification treatment of thermally conductive filler can improve the adsorption and compatibility of thermally conductive particles and silicone oil, and reduce the oil separation rate of TSGs. The prepared expanded graphite (EG)/paraffin wax (PW) composite phase change material (CPCM) has a relatively large latent heat of phase change, which can effectively control the temperature of the battery, but coating TSG between the battery and the CPCM can further enhance the heat dissipation effect of the battery.

Highly Anisotropic Thermal and Electrical Conductivities of Nylon Composite Papers with the Integration of Strength and Toughness

2021 ◽  
Author(s):  
Wen-Yan Wang ◽  
Chen-yu Li ◽  
Xiaodong Qi ◽  
Jinghui Yang ◽  
Yong Wang
Keyword(s):  
Mechanical Properties ◽  
Strength Of Materials ◽  
Conductive Composites ◽  
Electrical Conductivities ◽  
Thermally Conductive ◽  
Nylon Composite ◽  
Strength And Toughness

ABSTRACT The mechanical properties of thermally conductive composites are the key to realize their applications. Strength of materials is of significance, nevertheless it also should be noticeable to concern the...

Personal thermal management by thermally conductive composites: A review

2021 ◽  
Vol 23 ◽  
pp. 100595
Author(s):  
Xiaohui Zhang ◽  
Xujiang Chao ◽  
Lun Lou ◽  
Jintu Fan ◽  
Qing Chen ◽  
...  
Keyword(s):  
Thermal Management ◽  
Conductive Composites ◽  
Thermally Conductive

Thermally conductive composites with hydroxylated boron nitrides for the efficient thermal management of superconducting coils

2021 ◽  
Vol 225 ◽  
pp. 109262
Author(s):  
Jun Min Kim ◽  
Seunghyun Song ◽  
Young Jin Hwang ◽  
Jae Young Jang ◽  
Sanggil Lee ◽  
...  
Keyword(s):  
Thermal Management ◽  
Conductive Composites ◽  
Boron Nitrides ◽  
Superconducting Coils ◽  
Thermally Conductive

Highly thermally conductive UHMWPE/NG composites with the segregated structure and their application for heat spreader

2020 ◽  
pp. 089270572096564
Author(s):  
Xiao Wang ◽  
Hui Lu ◽  
Jun Chen
Keyword(s):  
Thermal Conductivity ◽  
Laser Flash ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Heat Spreader ◽  
Conductive Composites ◽  
Compression Direction ◽  
Thermal Analyzer ◽  
Thermally Conductive ◽  
Plane Direction

In this work, ultra-high molecular weight polyethylene (UHMWPE)/natural flake graphite (NG) polymer composites with the extraordinary high thermal conductivity were prepared by a facile mixed-heating powder method. Morphology observation and X-ray diffraction (XRD) tests revealed that the NG flakes could be more tightly coated on the surface of UHMWPE granules by mixed-heating process and align horizontally (perpendicular to the hot compression direction of composites). Laser flash thermal analyzer (LFA) demonstrated that the thermal conductivity (TC) of composites with 21.6 vol% of NG reached 19.87 W/(m·K) and 10.67 W/(m·K) in the in-plane and through-plane direction, respectively. Application experiment further demonstrated that UHMWPE/NG composites had strong capability to dissipate the heat as heat spreader. The obtained results provided a valuable basis for fabricating high thermal conductive composites which can act as advanced thermal management materials.

scholarly journals Improving the Actuation Speed and Multi-Cyclic Actuation Characteristics of Silicone/Ethanol Soft Actuators

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 62 ◽  
Author(s):  
Boxi Xia ◽  
Aslan Miriyev ◽  
Cesar Trujillo ◽  
Neil Chen ◽  
Mark Cartolano ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Short Term Memory ◽  
Conductive Filler ◽  
Thermally Driven ◽  
Thermally Conductive ◽  
Ethanol Evaporation ◽  
Long Short Term Memory ◽  
Soft Actuators ◽  
Robotic Applications ◽  
Soft Composite

The actuation of silicone/ethanol soft composite material-actuators is based on the phase change of ethanol upon heating, followed by the expansion of the whole composite, exhibiting high actuation stress and strain. However, the low thermal conductivity of silicone rubber hinders uniform heating throughout the material, creating overheated damaged areas in the silicone matrix and accelerating ethanol evaporation. This limits the actuation speed and the total number of operation cycles of these thermally-driven soft actuators. In this paper, we showed that adding 8 wt.% of diamond nanoparticle-based thermally conductive filler increases the thermal conductivity (from 0.190 W/mK to 0.212 W/mK), actuation speed and amount of operation cycles of silicone/ethanol actuators, while not affecting the mechanical properties. We performed multi-cyclic actuation tests and showed that the faster and longer operation of 8 wt.% filler material-actuators allows collecting enough reliable data for computational methods to model further actuation behavior. We successfully implemented a long short-term memory (LSTM) neural network model to predict the actuation force exerted in a uniform multi-cyclic actuation experiment. This work paves the way for a broader implementation of soft thermally-driven actuators in various robotic applications.

Structural Design and Forming Method of Single-Curved Surface Structure Based on Miura-Origami

2016 ◽  
Author(s):  
Hairui Wang ◽  
Chunfang Guo ◽  
Yujie Li ◽  
Yahua Liu ◽  
Minjie Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Structural Design ◽  
High Efficiency ◽  
Circular Tube ◽  
Great Influence ◽  
Curved Surface ◽  
Structural Performance ◽  
Forming Process ◽  
Structural Support ◽  
Vacuum Forming

With the advantage of high adaptability, Miura-origami structure with curvature shows various engineering applications such as a sandwich between two stiff facings with curvature requirements and structural support to form a circular tube. In this research, a forming method of polymer circular tube with single-curved surface origami expressed by five parameters was established and its corresponding theory was solved considering forming rationality in actual manufacturing. The components of circular tube were fabricated by the vacuum forming process and then spliced together. We conducted numerical simulation to analyze the structural performance of the tube with five parameters and shown that these parameters have a great influence on energy absorbed performance. Finally, a male mold of a part with Arc Miura-origami structure was designed and fabricated. The parts with Arc Miura-origami were manufactured using vacuum forming process and then spliced and bonded together into a two-layer tube. This research may provide a method to design and fabricate Miura-origami structure with high efficiency and quality.

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