Study of mechanical, electrical and thermal properties of carbon nanotube incorporated cellulose nanocomposites

Abstract

Low cost, biodegradable, thin and flexible carbon nanotube (CNT)/cellulose nanocomposites have been prepared by varying the concentration of multi-walled carbon nanotubes (MWCNTs) up to 3.0 wt%. To attain effective CNT/cellulose composites uniform CNT dispersion is made by the adsorption of sodium dodecyl sulfate (SDS) on the CNT surface. The implications of incorporating CNTs in cellulose and electrical, structural and thermal properties of the composites are evaluated in this work. The field emission scanning electron microscope micrographs of the CNT/cellulose composites display the uniform attachment of CNTs on the surfaces of all the fibers of cellulose sheet. The energy-dispersive x-ray spectroscopy analysis reveals that all the samples are composed of high content of C and O. The Fourier-transform infrared spectroscopy spectrum of the CNT/cellulose composites do not show any significant changes in the band position but the band intensities of -OH and -CH2 groups are increased. X-ray diffraction patterns indicate that the crystallinity of the composites is improved with increasing CNT concentration. The dominant weight loss of all the samples is observed between 566-663 K. A gradual decrease of sheet resistance of the composites can be observed due to the formation of electrically conducting CNT network on the surfaces of the all fibers of the cellulose sheet and the nanocomposites exhibit remarkably low sheet resistance varying from 6.5 kΩ/sq. to 0.04 kΩ/sq. The conductivity of the nanocomposites increases with the increase of incorporating wt% of MWCNTs and becomes 2.34 S/m. The conductivity of the nanocomposites also increases with the increase in temperature indicating the semiconducting nature of the composites. The activation energy of all the samples are decreased in high temperature region (358 K) compared to the low temperature region (298 K). Flame retardancy test indicates that the CNT/cellulose sheet exhibits an improved flame retardant performance. The sheet resistance is slightly increased in bending state compared to the flat condition of the composites. CNT/cellulose composites shows mechanical flexibility, which is desirable for flexible electronic devices. The CNT/cellulose nanocomposites will find applications in foldable energy storage electronic devices as well as in other advanced technological fields.