Characterization of electrical and thermal properties of carbon nanotube/epoxy composites

Abstract

The electrical and thermal conductivity of pristine, oxidized, and fluorinated single-wall/multi-wall carbon nanotube (CNT) mixtures, dispersed in epoxy, were investigated as a function of CNT concentration. The effect of fabrication parameters, such as stirring rate and degree of epoxy pre-curing, on CNT dispersion was analyzed. The electrical conductivity increased by 10 and 6 orders of magnitude for pristine and oxidized CNT composites, respectively, relative to neat epoxy, while fluorinated CNT composites showed no increase in electrical conductivity. An increase of up to 5.5% was observed in thermal conductivity for pristine CNT composites while oxidized and fluorinated CNTs provide less enhancement in thermal conductivity. A micromechanics model, based on the composite cylinders method, was implemented to study the electrical and thermal conductivity of these composites. Effects in electrical and thermal conduction, such as electron hopping and thermal interface resistance, respectively, were incorporated into the model to accurately simulate the acquired experimental results.