Influence of single-walled carbon nanotubes’ diameter and length on the thermal conductivity of polymer composites

Zaw Ye Aung,Pavel Prosuntsov,Sergey Reznik

doi:10.1051/matecconf/201822403018

Abstract

Physical properties of composite materials can be improved by carbon nanotubes (CNTs). However, the thermal resistance between the polymer matrix and CNT at nanoscale can result in lower thermal conductivity. The paper analyses influence of CNTs’ diameter and length on effective thermal conductivity in epoxy-based composites. It analyses the effect of the diameters, lengths and volumetric fraction of CNT on composites’ thermal conductivity.

Highlights

Conventional polymer composite materials (PCM) have a relatively low thermal conductivity: 0.45 W/(m·K) for glass-fibre reinforced polymers, 0.25 W/(m·K) for organic fiber reinforced polymer, 0.8 W/(m·K) for carbon fiber reinforced polymer, which can result in large temperature changes, and lead to significant deformations
Carbon nanotubes (CNTs) are in high demand because of their unique electrical and mechanical properties. These properties are more likely to occur in single-walled CNTs (SWCNT), rather than in multilayer CNTs due to the latter’s defect-free structure and low density (1.33-1.40 g/cm3) [1,2,3,4]
This paper considers the case of an epoxy binder with 0.25 W/ (m·K) thermal conductivity containing uniformly distributed CNT with 1 ± 2 ηm characteristic diameter and 100 ± 500 ηm lengths

Summary

Introduction

Conventional polymer composite materials (PCM) have a relatively low thermal conductivity: 0.45 W/(m·K) for glass-fibre reinforced polymers, 0.25 W/(m·K) for organic fiber reinforced polymer, 0.8 W/(m·K) for carbon fiber reinforced polymer, which can result in large temperature changes, and lead to significant deformations. The Monte Carlo method was used in [6] to theoretically establish thermal conductivity of PE with single-walled CNTs. The volume fraction of SWCNTs constituted 0.006, 0.03, and 0.06. In practice, polymer composites very rarely demonstrate thermal conductivity that high New software packages, such as DIGIMAT-FE, open up opportunities for predicting the characteristics of nanomodified materials by taking various structural features into account. Elastomers with less than 0.1 vt % CNT were not considered, since it was found that small volume fractions of CNT do not improve the polymer’s thermophysical characteristics This being said, the low CNT content in the polymer during polymerization enables the cross-linking of macromolecules relative to the structural centers and increases toughness, bending and compression strength.

Calculation of coefficient of thermal conductivity

Conclusion