Use of novel polyetheralkanolamine comb polymers as pigment dispersants for aqueous coating systems

The adsorption of a series of polyetheralkanolamine comb polymers characterized by a different length of the hydrophilic tail has been investigated at the carbon black/water interface by measuring adsorption isotherm, contact angle, wetting rate, zeta potential, and particle size distribution. Zeta potential measurements and adsorption layer thickness results suggest that polyetheralkanolamines with high ethylene oxide (EO) content provide only steric stabilization and they adsorb at the interface with the ethylene oxide chains in a coil conformation. The thickness of the adsorbed layer increases with increasing EO units; however, the surface tension and interfacial tension decrease with increasing EO content. Adsorption isotherms show that most of the added polyetheralkanolamine adsorbs onto the carbon black and only a small amount stays in the water phase. When treated with a polyetheralkanolamine, carbon black dispersions show uniform (unimodal) and narrow particle size distribution with very small median sizes of about 0.10 μm. The pigment concentrates containing the polyetheralkanolamine show excellent color compatibility in various decorative commercial white paints containing a wide range of resins and exhibit low viscosity with nearly Newtonian flow behavior. Presented at the 2006 FutureCoat! Conference, sponsored by the Federation of Societies for Coatings Technology, in New Orleans, LA, on November 1–3, 2006.