Development of water-based thermal insulation paints using silica aerogel made from incineration bottom ash

Abstract

In this work, silica aerogel (SA) powder is fabricated through a sustainable method from incineration bottom ash. The fabricated SA has a low thermal conductivity of 0.025 W/mK, high surface area of 786 m2/g, and high porosity of 96.36%. The thermal analysis of SA powder shows it has a stable hydrophobicity up to 418 °C. The SA powder has been mixed into water-based paints to develop a high efficient thermal insulation paint with inproved thermal insulaton properties. Different percentage of SA were mixed into the paint samples to prepare the silica aerogel thermal insulation paint (SATIP) and their physical properties were studied. The SATIP samples were then coated on cement board substrates. The thermal conductivity, water resistance, durability and insulation performance of the samples were investigated and evaluated systematically. The scrub resistance of SATIP can be improved significantly by 219% after adding 5 vol% SA powder. And by adding 20 vol% of SA into the SATIP, it achieves up to 12 °C surface temperature reduction improvement compare to the one without SA on the heated plate at 60 °C, and 1 °C in-chamber temperature reduction with external temperature of 44.6 °C. The spectral reflectance analysis demonstrates that the improvement of the thermal insulation performance of the SATIP is attributed to the thermal insulation property of SA and proves that the developed SATIP is color insensitive and has wider applications. The results demonstrated a low-cost and scalable process fabricates SA with superor properties. The developed SATIP has a great potential for application in sustainable and green buildings for energy saving.