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

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.

2021 ◽  
Vol 16 (2) ◽  
pp. 042-047
Author(s):  
Yanfei Bian ◽  
SHI Jian-zhou ◽  
XIE Ming-jun ◽  
CAI Meng

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)).


2007 ◽  
Vol 124-126 ◽  
pp. 1079-1082 ◽  
Author(s):  
Sung Ryong Kim ◽  
Dae Hoon Kim ◽  
Dong Ju Kim ◽  
Min Hyung Kim ◽  
Joung Man Park

Thermal properties of PEEK/silicon carbide(SiC) and PEEK/carbon fiber(CF) were investigated from ambient temperature up to 200°C measured by laser flash method. Thermal conductivity was increased from 0.29W/m-K without filler up to 2.4 W/m-K with at 50 volume % SiC and 3.1W/m-K with 40 volume % carbon fiber. Values from Nielsen theory that predicts thermal conductivity of two-phase system were compared to those obtained from experiment.


RSC Advances ◽  
2019 ◽  
Vol 9 (62) ◽  
pp. 36316-36323 ◽  
Author(s):  
Xiaolei Zheng ◽  
Bianying Wen

The selective distribution of thermally conductive fillers in a co-continuous polymer blends provides an industrialized preparation method that takes into account both the properties and functions of thermally conductive composites.


Author(s):  
Muhammad Omer Khan ◽  
Ellen Chan ◽  
Siu N. Leung ◽  
Hani Naguib ◽  
Francis Dawson ◽  
...  

This paper studies the development of new multifunctional liquid crystal polymeric composites filled with graphene nano platelets (GNPs) for electronic packaging applications. A series of parametric studies were conducted to study the effect of GNP content on the thermal conductivity of LCP-based nanocomposites. Graphene, ranging from 10 wt. % to 50 wt. %, were melt-compounded with LCP using a twin-screw compounder. The extrudates were ground and compression molded into small disc-shaped specimens. The thermal conductivity of LCP matrix was observed to have increased by more than 1000% where as the electrical conductivity increased by 13 orders of magnitude with the presence of 50 wt% GNP fillers. The morphology of the composites was analyzed using SEM micrographs to observe the dispersion of filler within the matrix. These thermally conductive composites represent potential cost-effective materials to injection mold three-dimensional, net-shape microelectronic enclosures with superior heat dissipation performance.


Author(s):  
Matthew I. Ralphs ◽  
Nicholas Roberts

Carbon nanotubes (CNTs) exhibit extraordinary mechanical and thermal properties and as such have become the subject of large research interest. Furthermore, CNTs in a polymer matrix have been shown to significantly enhance the thermal conductivity of the polymer/CNT composite in some cases. A few areas of application for this work are thermal interface materials, thermally conductive composites used in aerospace applications, and polymer heat exchangers. In each of these applications the purpose of the polymer or epoxy is to take advantage of the mechanical properties or chemical inertness. The current issue with their adoption is still the poor thermal conductivity. One approach to overcoming this issue is to embed thermally conductive materials into the host material in low concentrations to enhance the effective thermal conductivity. There has been a significant amount of work in this area, but we are far from an understanding that allows us to design a nanocomposite that gives the desired thermal conductivity (specifically in the high thermal conductivity range). This work explores the role that chemical modification (functionalization) of the CNT can play in tailoring thermal transport properties of the composite under strain. It is expected that the functionalization process would have some effect on conduction between the CNT and the polymer matrix and therefore either increase or decrease the ability of the composite to transport thermal energy. This paper focuses on three different functionalizations of CNT and explores the thermal conductivity of a polymer/CNT composite that uses polydimethylsiloxane (PDMS) as the matrix. The three functionalizations of CNTs considered are that of unfunctionalized, functionalized with a carboxyl group (-COOH), and functionalized with a hydroxyl group (-OH). The CNTs used in this study are strictly multi-walled carbon nanobutes (MWCNTs) purified to 95%. The effect of these three functionalizations on the overall thermal conductivity of the composite is evaluated through experimental methods with a stepped bar apparatus at various levels of strain on the composite sample. Results show that, while functionalization of the CNT may affect the CNT/PDMS bond, the stepped bar apparatus does not provide enough precision on the level of strain placed on the sample for a comparison across functionalizations. Future work will try to elucidate both the effect of strain and functionalization using multiple thermal conductivity measurement techniques.


2012 ◽  
Vol 729 ◽  
pp. 80-84 ◽  
Author(s):  
András Suplicz ◽  
József Gábor Kovács

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.


2016 ◽  
Vol 881 ◽  
pp. 117-122
Author(s):  
Flavia dos Reis Gonçalves ◽  
Daniel Thomazini ◽  
Maria Virginia Gelfuso

In this work, CaCuxTiyO12 ceramics (2.7 ≤ x ≤ 3.3 and 3.25 ≤ y ≤ 4.75), related to excess and deficiency of CuO-TiO2 eutectic phase have been synthesized by coprecipitation method. The crystalline phases in the ceramics were identified by X-ray diffraction patterns, and the pellets have mainly presented CCTO and also exhibited CuO, TiO2 and CaTiO3 as secondary phases. The thermal conductivity of the ceramics was determined using the laser flash method in the temperature range of 300-1000 K. It was observed a decrement in thermal conductivity values as the amount of the eutectic phase decreased. The electrical DC conductivity has been measured by the two-probe method from 300-1000 K and it has been noted that both grain size and amount of eutectic phase influenced the electrical conductivity results.


2011 ◽  
Vol 391-392 ◽  
pp. 282-286 ◽  
Author(s):  
Jun Peng Li ◽  
Shu Hua Qi ◽  
Fan Xie

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.


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