Correlation of Silicone Incorporation into Hybrid Acrylic Coatings with the Resulting Hydrophobic and Thermal Properties

A series of high-solids hybrid silicone−acrylic latexes, with varying silicone concentrations and reactivities, was prepared via miniemulsion polymerization. The properties of the resulting coatings have been correlated with their structure and the extent of silicone grafting. The highest silicone incorporation was obtained with silicones containing two reactive vinyl groups polymerized by a semicontinuous method with a delayed addition of neat monomer. It was found that the amount of silicone grafted to the acrylic chains, not the overall total amount in the formulation, was the main factor affecting film properties. Hydrophobicity, water resistance, and thermal stability all increased with the amount of grafted silicone. Coatings that contained high levels of nongrafted silicone displayed separate submicrometer silicone phases and exhibited inferior properties. When silicone was incorporated into the acrylic particles, the total drying time of the coating was shorter, and the water distribution—as deter...