Effect of dispersant surfactants on the properties of alumina-carbon nanotubes nanocomposites

Gum Arabic (GA), Sodium Dodecyl Sulfate (SDS) and their mixture were used for the dispersion of multi-wall carbon nanotube (CNT) in an alumina matrix. A good dispersion at low loadings (0.5-1 mass%) of CNTs in alumina was achieved by a bath ultrasonication method. Dispersions were evaluated by UV/vis spectroscopy and agglomerate size analyzer. The mixture of GA and SDS produced good dispersion as compared to GA and SDS alone. Nanocomposite powders were sintered by Spark Plasma Sintering (SPS). Electron microscopic analysis, electrical and mechanical characterizations of sintered discs were carried out to evaluate the effectiveness of the different surfactants. The mixture of GA and SDS produced homogeneously distributed and agglomerate-free CNT-alumina nanocomposites with higher electrical conductivity and indentation fracture toughness as compared to nanocomposites prepared using GA and SDS alone.