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...

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 Development of Thermally Conductive Polymer Materials and their Investigation

2012 ◽  
Vol 729 ◽  
pp. 80-84 ◽  
Author(s):  
András Suplicz ◽  
József Gábor Kovács
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Thermal Conduction ◽  
Filler Content ◽  
New Products ◽  
Conductive Polymer ◽  
Polymer Materials ◽  
Electronic Industry ◽  
Conductive Composites ◽  
Thermally Conductive

In the recent years a remarkable development can be observed in the electronics. New products of electronic industry generate more and more heat. To dissipate this heat, thermally conductive polymers offer new possibilities. The goal of this work was to develop a novel polymer based material, which has a good thermal conduction. The main purpose during the development was that this material can be processed easily with injection molding. To eliminate the weaknesses of the traditional conductive composites low-melting-point alloy was applied as filler. Furthermore in this work the effect of the filler content on thermal conductivity, on structure and on mechanical properties was investigated.

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.

Microstructure and Mechanical Properties of ZrB2/h-BN Multiphase Ceramics by Low-Temperature Reactive Sintering

2016 ◽  
Vol 697 ◽  
pp. 510-514 ◽  
Author(s):  
Feng Rui Zhai ◽  
Ke Shan ◽  
Ruo Meng Xu ◽  
Min Lu ◽  
Zhong Zhou Yi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Fracture Strength ◽  
Solid Phase ◽  
Raw Materials ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Microstructure And Mechanical Properties ◽  
Multiphase Ceramics ◽  
Strength And Toughness

In the present paper, the ZrB2/h-BN multiphase ceramics were fabricated by SPS (spark plasma sintering) technology at lower sintering temperature using h-BN, ZrO2, AlN and Si as raw materials and B2O3 as a sintering aid. The phase constitution and microstructure of specimens were analyzed by XRD and SEM. Moreover, the effects of different sintering pressures on the densification, microstructure and mechanical properties of ZrB2/h-BN multiphase ceramics were also systematically investigated. The results show that the ZrB2 was obtained through solid phase reaction at different sintering pressures, and increasing sintering pressure could accelerate the formation of ZrB2 phase. As the sintering pressure increasing, the fracture strength and toughness of the sintered samples had a similar increasing tendency as the relative density. The better comprehensive properties were obtained at given sintering pressure of 50MPa, and the relative density, fracture strength and toughness reached about 93.4%, 321MPa and 3.3MPa·m1/2, respectively. The SEM analysis shows that the h-BN grains were fine and uniform, and the effect of sintering pressure on grain size was inconspicuous. The distribution of grain is random cross array, and the fracture texture was more obvious with the increase of sintering pressure. The fracture mode of sintered samples remained intergranular fracture mechanism as sintering pressure changed, and the grain refinement, grain pullout and crack deflection helped to increase the mechanical properties.

scholarly journals Properties of High-Strength Flowable Mortar Reinforced with Palm Fibers

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Eethar Thanon Dawood ◽  
Mahyuddin Ramli
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Test Results ◽  
Palm Fiber ◽  
Toughness Index ◽  
Strength And Toughness

This study was conducted to determine some physical and mechanical properties of high-strength flowable mortar reinforced with different percentages of palm fiber (0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6% as volumetric fractions). The density, compressive strength, flexural strength, and toughness index were tested to determine the mechanical properties of this mortar. Test results illustrate that the inclusion of this fiber reduces the density of mortar. The use of 0.6% of palm fiber increases the compressive strength and flexural strength by about 15.1%, and 16%, respectively; besides, the toughness index (I5) of the high-strength flowable mortar has been significantly enhanced by the use of 1% and more of palm fiber.

A Study on Thermal and Electrical Conductivities of Ethylene-Butene Copolymer Composites with Carbon Fibers

2021 ◽  
Vol 36 (4) ◽  
pp. 417-422
Author(s):  
Y. Hamid ◽  
P. Svoboda
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Carbon Fiber ◽  
Electric Conductivity ◽  
Carbon Fibers ◽  
Mechanical Strain ◽  
Electric Resistance ◽  
Resistance Change ◽  
Electrical Conductivities ◽  
Fiber Sample

Abstract Ethylene-butene copolymer (EBC)/carbon-fiber (CF) composites can be utilized as an electromechanical material due to their ability to change electric resistance with mechanical strain. The electro-mechanical properties and thermal conductivity of ethylene butene copolymer (EBC) composites with carbon fibers were studied. Carbon fibers were introduced to EBC with various concentrations (5 to 25 wt%). The results showed that carbon fibers’ addition to EBC improves the electric conductivity up to 10 times. Increasing the load up to 2.9 MPa will raise the electric resistance change by 4 500% for a 25% fiber sample. It is also noted that the EBC/CF composites’ electric resistance underwent a dramatic increase in raising the strain. For example, the resistance change was around 13 times higher at 15% strain compared to 5% strain. The thermal conductivity tests showed that the addition of carbon fibers increases the thermal conductivity by 40%, from 0.19 to 0.27 Wm–1K–1.

Thermal-Structural Performance of Orthotropic Pin Fin in Electronics Cooling Applications

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
A. F. M. Arif ◽  
Syed M. Zubair ◽  
S. Pashah
Keyword(s):  
Heat Sink ◽  
Structural Response ◽  
Electronics Cooling ◽  
Base Plate ◽  
Thermal Design ◽  
Heat Flow Rate ◽  
Thermal Interface ◽  
Conductive Composites ◽  
Thermally Conductive ◽  
As Stress

Thermally conductive composites as compared to metals have reduced density, decreased oxidation, and improved chemical resistance, as well as adjustable properties to fit a given application. However, there are several challenges that need to be addressed before they can be successfully implemented in heat sink design. The interface between the device and heat sink is an important factor in the thermal design of microelectronics cooling. Depending on the thermal interface conditions and material properties, the contact pressure and thermal stress level can attain undesirable values. In this paper, we investigate the effect of thermal interface between the fin and base plate on thermal-structural behavior of heat sinks. A coupled-field (thermal-structural) analysis using finite element method is performed to predict temperature as well as stress fields in the interface region. In addition temperature and heat flow rate predictions are supported through analytical results. effect of various interface geometrical (such as slot-depth, axial-gap, and radial-gap) and contact properties (such as air gap with surface roughness and gaps filled with interface material) on the resulting thermal-structural response is investigated with respect to four interface materials combinations, and it is found that the thermal performance is most sensitive to the slot-depth compared to any other parameter.

scholarly journals Simultaneous Enhancement of Strength and Toughness of PLA Induced by Miscibility Variation with PVA

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1178 ◽  
Author(s):  
Yanping Liu ◽  
Hanghang Wei ◽  
Zhen Wang ◽  
Qian Li ◽  
Nan Tian
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Fracture Strain ◽  
Electrospun Fiber ◽  
Structural Evolution ◽  
Amorphous Structure ◽  
Poly Lactic Acid ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
Strength And Toughness

The mechanical properties of poly (lactic acid) (PLA) nanofibers with 0%, 5%, 10%, and 20% (w/w) poly (vinyl alcohol) (PVA) were investigated at the macro- and microscale. The macro-mechanical properties for the fiber membrane revealed that both the modulus and fracture strain could be improved by 100% and 70%, respectively, with a PVA content of 5%. The variation in modulus and fracture strain versus the diameter of a single electrospun fiber presented two opposite trends, while simultaneous enhancement was observed when the content of PVA was 5% and 10%. With a diameter of 1 μm, the strength and toughness of the L95V5 and L90V10 fibers were enhanced to over 3 and 2 times that of pure PLA, respectively. The structural evolution of electrospun nanofiber was analyzed by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Although PLA and PVA were still miscible in the concentration range used, the latter could crystallize independently after electrospinning. According to the crystallization behavior of the nanofibers, a double network formed by PLA and PVA—one microcrystal/ordered structure and one amorphous structure—is proposed to contribute to the simultaneous enhancement of strength and toughness, which provides a promising method for preparing biodegradable material with high performance.

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