Preparation and characterization of a reflective and heat insulative coating based on geopolymers

A reflective heat insulation coating was prepared using a geopolymer, which was mainly made of sodium silicate solutions and metakaolin, as the primary film forming material before adding sericite powder, talcum powder, titanium dioxide and hollow glass microspheres as fillers. This coating is a new, environmentally friendly inorganic coating with many capabilities, such as good water-retention, simple spraying, the compacted paint, high durability, dirt resistance, high reflectivity and remarkable heat insulation. The results indicate a titanium dioxide content of approximately 12% yields 6% hollow glass microspheres yielded a reflective heat insulation coating with a reflectivity over 90% and thermal insulation performance (internal and external surface temperature difference) of up to 24 °C. These mechanical and insulative properties could achieve the China National Standard (GB/T25261-2010).