Synthesis of CaCO3-Based Hyperdispersants and Their Application in Aqueous Coatings

Abstract

As an essential pigment particle in white water-based coatings, light calcium carbonate (CaCO3) is difficult to disperse in water-based systems. The hard-to-disperse particles agglomerate, causing the viscosity of the coating to rise, which in turn affects the quality of the coating. Therefore, in order to obtain efficient dispersion, the hyperdispersant SSS–MPEGA–DMAEA (SMD) has been prepared in this study using sodium styrene sulfonate (SSS), polyethylene glycol monomethyl ether acrylate (MPEGA), and dimethylaminoethyl acrylate (DMAEA) as monomers through aqueous solution polymerization. Firstly, we utilized the central composite design method to conduct mathematical modeling of the monomer ratios so as to optimize the dispersion performance of the hyperdispersants. Secondly, the structural characteristics and molecular weight distribution of SMD were characterized by 1H NMR spectroscopy and GPC. Then, the effect of SMD on the dispersion of the CaCO3 slurry was investigated through particle size distribution and TEM measurements. Finally, we applied the SMD in aqueous white coatings and tested the surface properties of the paint film by SEM as well as the stability of the paint film. The results showed that SMD can significantly reduce the viscosity and particle size of the CaCO3 slurry. The waterborne coatings prepared by SMD had good storage stability and corrosion resistance, so the materials owned broad application prospects.