The enhanced surface properties of geopolymer inorganic coatings by adding with MgO

This paper mainly studies an inorganic coating based on geopolymer technology. Metakaolin is used as raw material, and water glass solution is used as alkali activator to prepare geopolymer. The surface properties including crack resistance and scrub resistance of the obtained coating were improved by adding certain amount of resin and fillers such as silicone acrylic emulsion, mica powder, and MgO powder. The results show that when the contents of silicone acrylic emulsion, mica powder, and MgO powder are 19.00%, 3.20%, and 2.16–2.86%, respectively, the surface properties of the coating are optimal. Especially noteworthy is that adding MgO can enhance the surface properties of the prepared coating, the mechanism of which can be rationalized by the inhibited shrinkage of the coating via microcrack deformation, the enhanced compactness and the filled pores of the coating upon adding MgO. In addition, the flame retardancy of the samples was explored through thermal analysis and cone calorimeter.