A new member of solar heat-reflective pigments: BaTiO₃ and its effect on the cooling properties of ASA (acrylonitrile-styrene-acrylate copolymer)

Although barium titanate (BaTiO₃, BT) has been extensively used in manufacturing electronic materials, less attention has been paid to the area of cool material. Herein, BT was first used as solar heat-reflective pigment, aiming to be possibly applied in cool roof for cooling purpose. Specifically, four types of BT with different particle size were added into acrylonitrile-styrene-acrylate copolymer (ASA) matrix to fabricate composite cool materials. The solar reflectance and cooling effect were investigated by ultraviolet-visible-near infrared (UV–Vis–NIR) spectral measurement and temperature test, respectively. The results of the solar spectral measurement suggested that the addition of BT particles significantly improved NIR reflectance of ASA by 2–3 times. Besides, the total solar reflectance firstly increased with the increasing average particle size up to 406 nm and then leveled off. Meanwhile, a significant decrease (about 10 °C) was achieved in the indoor temperature test when BT particles were introduced. As for the outdoor temperature test, the final temperature of ASA/BT (406 nm) and ASA/BT (1068 nm) was different though their solar reflectance values were close, indicating that the temperature test was a great complementary instrument of the solar spectral measurement.