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Authors Gong, P. ; Buahom, P. ; Tran, M.-P. ; Saniei, M. ; Park, C. B. ; Pötschke, P.
Title Heat transfer in microcellular polystyrene/multi-walled carbon nanotube nanocomposite foams
Date 01.11.2015
Number 45947
Abstract We report the heat-transfer characteristics of polystyrene (PS)/multi-walled carbon nanotube (MWCNT) nanocomposite foams with a large expansion ratio (18-fold) and a microcellular cell size (5 µm) that have never been achieved before. These PS/MWCNT foams exhibited excellent thermal insulation performance even without insulation gas. The 5 µm-sized cells in these PS/MWCNT foams are small enough to induce Knudsen effect, and also lead to a distinct radiation behavior that has never been reported; that is, because of the unique synergy of the small cells and the MWCNTs, the short wavelength radiation below the cell size is 100% blocked while the long wavelength radiation over the cell size is strongly attenuated. We made an in-depth analysis of the heat transfer through the PS/MWCNT foams using models. Adding 2 wt% MWCNTs into the PS matrix, 86% of the radiative thermal conductivity was effectively blocked, and the radiative contribution was reduced to 3.5% of the total thermal conductivity. However, the MWCNTs increased the solid conductivity of the PS/MWCNT foams due to their inherently high thermal conductivity. So, a compromised content of 1 wt% MWCNTs was added to optimize solid conduction and radiation, and thereby to minimize the total thermal conductivity to 32.8 mW/m K.
Publisher Carbon
Wikidata
Citation Carbon 93 (2015) 819-829
DOI https://doi.org/10.1016/j.carbon.2015.06.003
Tags fiber-composite foams thermal-conductivity polyolefin foams low percolation blowing agent die geometry blends insulation dispersion crystallization

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