THERMAL DIFFUSIVITY MEASUREMENTS OF CONDUCTIVE NANOCOMPOSITES BASED ON EVA COPOLYMER FILLED WITH EXPANDED AND UNEXPANDED GRAPHITE
In this research, thermal diffusivity of composites based on Ethylene-vinyl acetate copolymer (EVA) filled with two kinds of reinforcement graphite materials was investigated. The reinforcement graphite fillers were untreated natural graphite (UG) and expanded graphite (EG); both of the graphite powders had originally similar diameters, 5-6μm. Composite samples up to 29.3％ graphite particle volumetric concentrations (50％ weight concentration) were prepared by melt-mixing process in a Brabender Plasticorder. Upon mixing the EG exfoliates in this films having nanosized thicknesses evidenced by TEM micrographs. Thus, thermal diffusivity and electrical conductivity of nanocomposites based on the ethylene-vinyl acetate (EVA) matrix filled with nanostructuralized expanded graphite and standard, micro-sized graphite were investigated. From the experimental results we may deduce that the electrical conductivity was not only a function of filler concentration, but also strongly dependent on graphite structure. The percolation concentration of the filler was found to be 15.17 vol.％ for micro-sized natural graphite, whereas the percolation concentration of the filler in nanocomposites filled with expanded graphite was much lower, about 5.6 vol.％. Electrical conductivity of nanocomposites was also much higher than electrical conductivity of composites filled with micro-sized filler at similar concentrations. Similarly the values of the thermal diffusivity for the nanocomposites, EG filled EVA, was significantly higher than the thermal diffusivity of the composites filled with micro-sized filler, UG filled EVA, at similar concentrations. For 29.3％ graphite particle volumetric concentrations, the thermal diffusivity was 8.23 x10-7 m2/s for EG filled EVA and 6.14 x10-7 m2/s for UG filled EVA. Thermal diffusivity was measured by flash method.
Ismail H. Tavman Alpaslan Turgut Henrique Massard da Fonseca Helcio R. B. Orlande Renato M. Cotta Maycon Magalhaes
Mechanical Engineering Department Dokuz Eylul University 35100 Bornova- Izmir, Turkey COPPE/UFRJ Department of Mechanical Engineering Federal University of Rio de Janeiro – UFRJ Rio de J
国际会议
The Ninth Asian Thermophysical Properties Conference(第九届亚洲热物理性能会议 ATPC 2010)
北京
英文
334-339
2010-10-19（万方平台首次上网日期，不代表论文的发表时间）