Stabilization Mechanism of the Reconstituted Emulsion of Polyacrylate Redispersible Powder

Polyacrylate redispersible powder was prepared from polyacrylate emulsion with a soft-core and hard-shell configuration by spray drying. The effect of polyvinyl alcohol (PVA) solution as a protective colloid on the redispersibility of the polyacrylate powder was investigated, along with the stabilization of the reconstituted emulsion. The results show that bulk carboxylic ions were formed on the particle surface when the pH value was between 9.0 and 10.0, leading to a high zeta potential and strong electrostatic repulsion force among the latex particles of the reconstituted emulsion. The hydrophilic group -OH of the protective colloid PVA combined with water molecules and the hydrophobic polyethylene long-chain groups were adhered onto the particle surface of the reconstituted emulsion latex, which induced steric hindrance between latex particles and prevented particle aggregation. The synergistic effect of the strong electrostatic repulsion force produced by carboxylic ions and the space steric hindrance generated by the PVA solution provided excellent redispersibility and stability to the reconstituted emulsion.