Stabilizing pigments in water-based paint systems is a complex process that requires a highly robust pigment dispersion due to the need for compatibility in different coatings systems. In this month’s column we will evaluate the development of surfactant molecules for use as a carbon black pigment dispersant. To determine the best conditions for stabilization, compatibility and performance of the pigment dispersion, variations in the size of the polymeric chain that make up the tail of the surfactant were made and tested. In next month’s column we will finish this up by evaluating the effect of the amount of the dispersant in the formulation of the pigment concentrate, and data will be presented. I would like to thank Alann de O.P. Bragatto, Brandon L. da Silva, and Fabrício G. Pereira for generating the data for this and next month’s articles.
Carbon black is one of the most difficult pigments to disperse and stabilize in water. This is due to its highly hydrophobic character, with a composition of 90 to 99% elemental carbon. The primary particles tend to aggregate when the pigment is added to water, so a dispersant is needed to stabilize it. The choice of a suitable dispersant is essential to provide an optimized dispersion of the pigment in water, to minimize process time and energy costs. It will also maximize the pigment content in the formulation and ensure the stability of the pigment concentrate.