Thermal conductivities of composites in several types of dispersion systems

Agari, Yasuyuki; Ueda, Atsushi; Nagai, Susumu

doi:10.1002/app.1991.070420621

Cited by 163 publications

(86 citation statements)

References 7 publications

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“…In previous studies of high thermal conductivity composites, the packing ratio and shape factor of the filler materials are mainly investigated [34] since the composites were usually prepared by MD or similar methods. Various models for estimating the thermal conductivity [34,[37][38][39][40] of the composites have determined that the shape characteristics of the filler are important parameters to enhance the thermal conductivity. However, for discussion of the PCC prepared by HP, an additional shape parameter of the PCM matrix should be taken into consideration.…”

Section: Discussionmentioning

confidence: 99%

High thermal conductivity phase change composite with percolating carbon fiber network

et al. 2015

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Section: Discussionmentioning

confidence: 99%

High thermal conductivity phase change composite with percolating carbon fiber network

et al. 2015

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“…Characteristics of TEG-polymer CM. interpenetrative components and impregnations; d) the structure of granular material and others [12,13]. Practically, the all of these models are developed for CM with fillers as spherical or cubic rigid particles and therefore it is possible to use the packing density coefficient F (maximal filler volume fraction within the volume).…”

Section: Resultsmentioning

confidence: 99%

Mechanism of thermal and electrical conductivity in polymer‐nanocarbon composites

Lazarenko

Вовченко

Prylutskyy

et al. 2009

Materialwissenschaft Werkst

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The electrical and thermal conductivity of nanocarbon filled polymers were studied by adding nanocarbon fillers (thermoexfoliated graphite (TEG) and dispersed TEG (nanoTEG)) to epoxy resin (ED) or polyethylene oxide (PEO). The content of filler in composite materials (CM) was (0.5 -10) wt%. The temperature range of the investigations was (77 -300) K for electrical conductivity and (150 -423) K for thermal conductivity, respectively. It was found that electrical conductivity of CM obeys percolation dependence with low critical concentration C cr $ (1 -2) wt% (j cr $ (0.56 -1.1) vol%) and characterised by a positive temperature coefficient. The thermal conductivity is approximately linear on nanocarbon content. The model describing the mechanisms of electrical and thermal conductivity of CM had been proposed. The basic parameters of this model are following: content of nanocarbon anisotropic particles and their distribution in polymer matrix; the contact thermal (electrical) resistance both between the filler particles and on the interface of two phases -polymer-carbon filler.Keywords: Nanocarbon filler; aspect ratio, electrical properties; thermal properties; porosity Die elektrische und thermische Leitfähigkeit von Nanokohlenstoff-Polymer-Kompositen (CM) wurde untersucht. Die Materialien wurden unter Zugabe von Nanokohlenstoff-Füllmaterialien (thermoexfoliertem Graphit (TEG) und dispergiertem TEG (nano-TEG)) zu Epoxidharzen (ED) oder Polyethylenoxid (PEO) hergestellt.Der Gehalt an Füllstoffen in den Kompositmaterialien betrug 0,5 bis 10 wt%. Für die elektrischen Messungen wurden die Untersuchungen im Temperaturbereich von 77 bis 300 K und für die thermischen Leitfähigkeitsmessungen im Bereich 150 bis 423 K durchgeführt. Es konnte gezeigt werden, dass die elektrische Leitfähig-keit von CM der Perkolationsabhängigkeit mit einer niedrigen kritischen Konzentration von C cr $ (1 -2) wt% (j cr $ (0.56 -1.1) vol%) folgt und durch einen positiven Temperaturkoeffizienten charakterisiert ist. Die thermische Leitfähigkeit ändert sich linear mit dem Nanokohlenstoffgehalt. Auf dieser Basis wurde ein Modell für die elektrische und thermische Leitfähigkeit von CM vorgeschlagen.

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“…Several models have been developed to predict the TC of fibre/polymer composite, such as Springer-Tasi model, Rayleigh model, Cheng-Vachon model, Nilessen model, Halpin-Tsai model and Agari Y model [12][13][14][15][16][17][18] . Goyanes et al [19] used Nilessen model to predict the TC of Al/PMMA composites and obtained unitary results.…”

Section: Relationship Of Tc With Mwcnt Loadingsmentioning

confidence: 99%

Investigation on the thermal conductivity of HDPE/MWCNT composites by laser pulse method

Chen

et al. 2009

Sci. China Ser. E-Technol. Sci.

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Thermal conductivity (TC) of high density polyethylene/multiwall carbon nanotube (HDPE/MWCNT) composite films was measured by laser pulse method. It is found that the TC increased quickly with the increase of MWCNT fraction when the volume fraction of MWCNT was below 3.35%. However, as the volume fraction of MWCNT was over 3.35%, the increasing rate became slow. A new percolation model was proposed based on the effect of MWCNT network to simulate the TC of HDPE/MWCNT composite films. The simulation result was in good agreement the experimental data well. In addition, the relationship of TC with the increase of temperature was also discussed. HDPE/MWCNT composite, thermal conductivity, percolation modelPositive temperature coefficient (PTC) polymer composites are temperature sensitive materials whose electric resistivity sharply increases with the increase of temperature in the PTC temperature range. Generally, the PTC polymer composites are synthesized by using polymer and conductive dopants, and the carbon black (CB) is the most popular dopant.Due to their unique auto-switch function, the CBfilled PTC polymer composites have been widely used in auto-control heat cable, plane heater and overrun current protecting device in the fields of petrochemistry, electric device, electric power, traffic, agriculture, stockbreeding, paper making and medical treatment [1,2] . However, to reach the percolation concentration (The filler concentration at which a pathway of the conductive filler is formed through the matrix), the PTC composites have to have a high loading of CB, which usually results in degradation of both mechanical and processing properties of the composites.Ideally, PTC materials should have low room temperature electric resistivity, low electric dopant loading and high PTC performance. MWCNT has high electrical conductivity, high network forming ability and lower cost, therefore, using MWCNT rather than CB as conductive filler is a research interest for many scientists [3,4] . He et al. synthesized a polymer PTC composite with MWCNT and high-density polyethylene (HDPE). It was found that the room temperature resistivity of the HDPE/ MWCNT PTC composites decreased from 10 15 Ω·m to 10 4 Ω·m with 3 wt% MWCNT loading, while the PTC intensity of MWNT/HDPE composite with 5.4 wt% MWCNT could reach 1.1×10 4 [3] .Because the polymer PTC composites are mainly used to make temperature sensitive devices [5] , heat transport performance is very important for their application. However, the TC of MWCNT/polymer composites is rarely studied compared with their electrical conductivity. In the present work, the TC of HDPE/ MWCNT PTC composites was measured by laser pulse method. A new percolation model was developed to simulate the TC of HDPE/MWCNT composite.

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Thermal conductivities of composites in several types of dispersion systems

Cited by 163 publications

References 7 publications

High thermal conductivity phase change composite with percolating carbon fiber network

High thermal conductivity phase change composite with percolating carbon fiber network

Mechanism of thermal and electrical conductivity in polymer‐nanocarbon composites

Investigation on the thermal conductivity of HDPE/MWCNT composites by laser pulse method

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