Thermal Conductivity of Single-Walled Carbon Nanotube-PMMA Nanocomposites

Thermal Conductivity of Single-Walled Carbon Nanotube-PMMA Nanocomposites

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Thermal Conductivity of Single-Walled Carbon Nanotube/PMMA Nanocomposites Csaba Guthy 1 , Fangming Du 2 , Stijn Brand 1 , John E. Fischer 1 , Karen I. Winey 1, 2 . 1 Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, USA. 2 Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA. ABSTRACT: Due to their exceptional thermal properties, single-wall carbon nanotubes (SWNT) are considered as very promising filler materials for improving the thermal conductivity of conventional polymers. We carefully investigated the thermal conductivity of SWNT/PMMA nanocomposites with SWNT loading in the range up to10 wt% using the comparative technique. The samples were prepared by coagulation method. We demonstrated moderate improvement in the composites' thermal conductivity of about 250% at 10wt%. The experimental results were analyzed using the versatile Nielsen model, which takes into account many important factors, like the fillers aspect ratio and maximum packing fraction. The aspect ratio of SWNT material used to prepare our composites was determined by AFM and careful image analysis in order to use it as an input parameter in the Nielsen model. We obtained good agreement between our experimental results and the predictions of the Nielsen model. Based on our analysis we concluded that higher aspect ratio of filler material was needed to achieve better improvement in the composites thermal conductivities. One should also take steps in order to improve the thermal contact between the SWNT network and the matrix material. I. INTRODUCTION The exceptional thermal and mechanical properties of single wall carbon nanotubes (SWNT) make them a promising filler material for polymer composites. According to theoretical calculations [1] the thermal conductivity of a (10, 10) SWNT is 6000 W/mK which is higher than that of diamond. In addition, due to the very large aspect ratio of nanotubes (of the order of 2000 [2]) the percolation threshold for nanotube composites can be as low as 1% by volume. Based on this, theoretical models predict that an addition of even a low volume fraction of SWNTs would result in significant increase of a composite’s thermal conductivity. However, experimental values of thermal conductivity for polymer-SWNT composites are generally lower than those predicted by theory [2, 3, 4, 5]. Several studies [6,7] have suggested that a large interfacial thermal resistance at the nanotube-polymer interface and between the nanotubes themselves limits the thermal conductivity. An AFM study [8] has shown that the large aspect ratio of nanotubes is not preserved during the processing of nanotubes for composites. Experimental investigations of heat transport in these systems are still scarce, especially those
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/18/2012 for the course PHYSICS 303 taught by Professor Ihn during the Spring '12 term at Swiss Federal Institute of Technology Zurich.

Page1 / 6

Thermal Conductivity of Single-Walled Carbon Nanotube-PMMA Nanocomposites

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online