Effect of amine-functionalized dispersant on cure and electrical properties of carbon nanotube/epoxy nanocomposites

The efficient dispersion of carbon nanotubes, CNTs in epoxy resin is a challenging task to reach the final properties of the competent nanocomposite. In this study, the CNT/epoxy nanocomposite was fabricated by solution mixing process using an amine-functionalized dispersant. The dispersion of CNTs in organic solvent was further improved using an ultrasonic horn. According to the data obtained from UV-vis spectroscopy, a minimum ultrasonication time of 10 min is necessary to obtain proper dispersion of CNTs in organic solvent. The cure behavior of epoxy resin containing different CNT loadings was investigated by dynamic DSC thermograms. The higher CNT loading lowers the initial curing temperature and the peak temperature mainly due to high thermal conductivity of CNT. The SEM micrographs of the fractured surfaces showed the effect of dispersant on proper dispersion of CNTs in epoxy. The electrical percolation threshold was measured at about 0.5 wt% of CNT. However, the conductivity results revealed the adverse effect of dispersant on the nanocomposite electrical properties, mainly due to dispersant adsorption and hence screening the CNTs surface charges.