Industrial & Engineering Chemistry Research, Vol.52, No.19, 6311-6317, 2013
Effect of Softwood Kraft Lignin Fractionation on the Dispersion of Multiwalled Carbon Nanotubes
Dispersion of carbon nanotubes has been a major obstacle for the application and utilization in composites. In this study, it was observed that a small amount of softwood Kraft lignin (SKL) could facilitate the dispersion of multiwalled carbon nanotubes (MWCNTs) in dimethylformamide (DMF) solutions. Classification of the technical SKL by solvent fractionation revealed distinct differences in MWCNT dispersibility. Using Raman spectroscopy the efficacy of the various SKL fractions to disperse MWCNT's in DMF was studied. Of the fractions investigated it was found that the methanol/methylene chloride (70/30, v/v) soluble fraction (F4SKL) performed the best. Characterization of the various fractions indicates that lignin structure and propensity to form intermolecular (pi-pi and hydrogen bonding) interactions is critical for MWCNT dispersion.