碳管管徑對奈米碳管/環氧樹脂複合材料熱傳導係數的效應

Effects of CNT Diameter on the Thermal Conductivities of MWCNT/Epoxy Composites

黃杰(Chieh Huang)

指導教授 ： 余念一

元智大學/工程學院/機械工程學系/碩士(2007年)

https://doi.org/10.6838/YZU.2007.00181

摘要

奈米碳管擁有優異的熱傳導性質，在本研究中，多壁奈米碳管以加強材的形式添加在環氧樹脂中以增加材料的熱傳導係數。我們分別使用兩組碳管，直徑小於10奈米和直徑介於40到60奈米之間的兩種碳管，和環氧樹脂均勻混合後並在常溫下固化，製成多壁奈米碳管/環氧樹脂複合材料。

多壁奈米碳管/環氧樹脂試片的熱傳導係數是利用瑞領公司所製作的熱傳導量測裝置LW-9021來測量。純環氧樹脂的熱傳導係數是0.23W/mK，而1 wt.%，3 wt.%和5 wt.%，碳管直徑40到60奈米的多壁奈米碳管/環氧樹脂複合材料的熱傳導係數比起純環氧樹脂提升效率分別是4.3%，11.7%和27.8%。而碳管直徑小於10奈米的多壁奈米碳管/環氧樹脂試片，跟純環氧樹脂比較起來，1 wt.%，3 wt.%和5 wt.% 多壁奈米碳管的提升效率分別是16.1%，37.8%和62.3%。

另外，利用艾胥比的微觀力學模型來估計多璧奈米碳管/環氧樹脂的熱傳導係數。在碳管直徑介於40到60奈米的這組數據中，模擬的結果和實驗的結果相當吻合。而直徑小於10奈米的數據來比較，實驗值和模擬值則有極大的差異。

關鍵字

奈米碳管 ； 環氧樹脂 ； 複合材料 ； 熱傳導係數

並列摘要

Carbon nanotubes (CNTs) exhibit excellent thermal as well as mechanical properties. In the present work, multi-walled carbon nanotubes (MWCNTs) are used as reinforcements to increase the thermal conductivity of epoxy resin. Two groups of MWCNTs are used – one with diameters being less then 10 nm and the other with diameters ranging between 40 to 60 nm. Epoxy and MWCNTs are well mixed and MWCNT/epoxy composites are cured at room temperatures.

The thermal conductivities of MWCNT/epoxy specimens are experimentally determined using a thermal conductivity apparatus, LW-9021 developed by Longwin Company. The average thermal conductivity of pure epoxy is 0.23 W/mK and the percentage in increase in average thermal conductivities of 1 wt.%-, 3 wt.%- and 5 wt.%-MWCNT/epoxy composites where the diameter of MWCNT is 40 – 60 nm is 4.3 %, 11.7 % and 27.8%, respectively, higher than that of pure epoxy. For the case of MWCNTs with smaller diameters D < 10 nm, the percentage increase in the average thermal conductivities of 1 wt.%-, 3 wt.%-, and 5 wt.%- MWCNT/epoxy composites is 16.1%, 37.8% and 62.3%, respectively, in comparison with that of pure epoxy.

The micromechanics model developed by Eshelby is employed to estimate the thermal conductivities of MWCNT/epoxy. The predicted results agree well with the experimental data of MWCNT/epoxy where the diameters of MWCNT range between 40 and 60 nm. The discrepancy between the experimental data and the predicted results for MWCNT/epoxy where the diameters of MWCNT are less than 10 nm, however, is significant using the microstructural parameters provided by the vendor.

並列關鍵字

CNT ； epoxy ； composite ； thermal conductivity

參考文獻

Bryning, M. B., Milkie, D. E., Islam, M. F., Kikkawa, J. M., and Yodh, A. G. (2005), “Thermal conductivity and interfacial resistance in single-wall carbon nanotube epoxy composite,” Applied Physics Letter, 89, 161909, pp. 1-3.

Chao, W. H. (2007), Effects of Microstructure on the Thermal Conductivities of Carbon Nanotubes, MS Thesis, Department of Mechanical Engineering, Yuan Ze University.

Eshelby, J. D. (1957), “The determination of elastic field of an ellipsoidal inclusion and related problems,” Proceedings of the Royal Society of London, A241, pp. 376-396.

Gojny, F. H., and Schulte, K. (2004), “Functionalisation effect on the thermo-mechanical behaviour of multi-wall carbon nanotube/epoxy-composites,” Composites Science and Technology, 64, pp.2303–2308.

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