Energy and Buildings, Vol.126, 170-176, 2016
Preparation and characterization of high NIR reflective pigments based in ultramarine blue
Buildings are responsible for at least 40% of energy use in most countries. High reflectance outdoor coatings can bring significant energy savings for building applications. In this context, ultramarine blue pigment (UB) has been modified to increase its near infrared reflectance by depositing a reflecting film based on TiO2 containing different types and concentrations of nanoparticles (alumina, titania and a mixture of them). The developed pigments were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and laser dispersion. For testing the performance of the modified pigments, they have been dispersed in a conventional waterborne paint at different percentages and characterized by UV-Vis-NIR spectrophotometry (measuring Total Solar Reflectance and CIE Lxaxbx). All the obtained paints increased the TSR in 2.65% when adding nanoparticles but the maximum value was obtained for an addition of 6 wt.% of titania nanoparticles. Higher contents of nanoparticles led to agglomeration reducing the reflectance in the final paint. (C) 2016 Elsevier B.V. All rights reserved.