Improving water resistance of all-acrylic emulsion resins using reactive surfactants

The replacement of conventional surfactants with reactive surfactants in emulsion polymerization is a promising strategy for improving the water resistance of waterborne coatings.  However, the appropriate use of reactive surfactants in emulsion polymerization to balance stability and water resistance is still a challenge. With all-acrylic polymer emulsions, due to their higher polarity, they are more difficult to stabilize during the polymerization in comparison to styrene-acrylic polymer emulsions.

In this presentation, the properties and application of a new reactive nonionic surfactant will be presented. The molecule was designed to react with the key monomers used in emulsion polymerization and to present surface activity similar to conventional nonionic surfactants. Polymerization of all-acrylic latexes were carried out using a combination of conventional anionic surfactant and the new reactive nonionic surfactant. The effect of surfactant composition on emulsion stability and water resistance was explored.

Emulsions polymerized with the reactive nonionic surfactant exhibited particle sizes in the range of 90-110 nm and excellent mechanical stability. Emulsions polymerized with the optimized composition of surfactants showed outstanding blush/whitening resistance. They absorbed about 85 wt% less water than the all-acrylic emulsion benchmark after immersion in water for 7 days. Using HPLC, We will also examine the incorporation of the reactive nonionic surfactant.