Production of Water Dispersible Carbon Nanotubes and Nanotube/Cellulose Composite

Abstract

Polymer wrapping methods have been used to disperse carbon nanotube (CNT) by using gelatin, an environment-friendly and easily decomposable biopolymer. The amino acid chain of gelatin becomes immobilized by the physical adsorption in the side wall of the CNTs through hydrophobic-hydrophobic interaction and results in the untangling of the CNT bundles. The dispersed solution remains stable for more than a month. Furthermore, this technique does not affect the physical properties of CNTs while enabling their dispersion in aqueous solutions. In addition, gelatin can be easily removed from the nanotubes after the dispersion of nanotubes by heating in water and filtration. Gelatin-dispersed CNTs are homogeneously mixed with the cellulose suspension and dried at room temperature to produce CNT/cellulose composite paper sheet. Adding multiwalled carbon nanotubes (MWNTs) in composite improves the mechanical, thermal, and electrical properties of cellulose. SEM investigation confirms the homogeneous distribution of MWNTs in the cellulose, which can be attributed to the improvement of its characteristics. Both sides of the CNT/cellulose sheet show uniform electrical conductivity, which is enhanced by increasing the MWNTs’ content. IR image of the sheet clearly shows the temperature homogeneity of the surface. Thermal stability and the flame retardancy of the sheet are also found to be improved. The sheet has also strong absorbing of electromagnetic waves, which make them important for microwave technology applications.