Near Infrared Reflection and Hydrophobic Properties of Composite Coatings Prepared from Hollow Glass Microspheres Coated with Needle-Shaped Rutile Shell

Infrared thermal reflective coating is an effective material to reduce building energy consumption and carbon emission. In this work, needle-shaped-rutile-shell-coated hollow glass microbeads (HGM) were prepared by surface modification of HGM and thermohydrolysis of TiCl4, and the possible shell formation mechanism was also proposed. The near infrared (NIR) reflectance of the coated HGM reached 93.3%, which could be further increased to 97.3% after the rutile shell crystallinity was improved by heat treatment. Furthermore, HGM/styrene–acrylic composite reflective coating was prepared on the surface of gypsum board by facile blending and coating methods, and the thermal insulation performance was measured by an indigenously designed experimental heat set-up. The results show that the composite coating prepared by HGM coated with rutile shell shows better NIR reflectance and thermal insulation performance than that prepared by pure organic coating and uncoated HGM. Meanwhile, it also shows better surface hydrophobicity, which is conducive to long-term and stable infrared reflection performance.