Self-cleaning acrylic water-based white paint modified with different types of TiO₂ nanoparticles

This paper aims to study the Improvements in self-cleaning property of the white acrylic water-based paint by addition of different percentages of three commercially available titanium dioxide (TiO₂) nanoparticles as additives. Then, due to the risk of destruction of polymeric materials in the presence of nanoparticles, degradation of dry paint film samples was investigated for 15 days using two important chalking and yellowing factors. Finally, the TiO₂-modified paint sample with the best performance and optimum percentage of TiO₂ nanoparticles that produced desired self-cleaning and dry film properties was introduced.

Self-cleaning and dry film properties of white acrylic water-based paint were investigated by addition of three various types of commercial available TiO₂ nanoparticles (SSP-25, STA-100 and KA-100). X-ray diffraction, transmission electron microscopy and Brunauer–Emmett–Teller were used for characterization of TiO₂ samples. Colorimetric tests in decolourization of C.I. Basic Red 46 (BR46) were used for determination of self-cleaning properties of TiO₂-modified paints in comparison with unmodified paint sample. Also, paints defects such as chalking and yellowing were tested along two weeks.

The results indicated that, in all types of TiO₂ nanoparticles, by increasing the amount of TiO₂ in modified paint, self-cleaning property of the samples was enhanced. The paint containing SSP-25 indicated better self-cleaning properties than others due to its larger surface area. However, its usage above 3.5 weight per cent caused yellowing and chalking defects in dried paint film.

In this research, TiO₂-modified paint sample with the best performance in both self-cleaning and mechanical properties was selected among the nine sets of prepared paint samples. All the materials used in this research such as acrylic resin and three types of TiO₂ nanoparticles are of industrial grade. Therefore, the introduced TiO₂-modified paint sample has the potential for the commercial production as a building exterior paint.

In the present study, an attempt at introducing a self-cleaning paint sample with acceptable mechanical properties using three types of commercially available TiO₂ nanoparticles as additives and industrial grade of acrylic resin which is the most commonly used water-based resin in building paints, as binder. As far as it was searched in the literatures, the parallel study of the self-cleaning and mechanical properties of paints has not been reported as noteworthy. Self-cleaning property of the acrylic water-based paint samples was investigated by adding three types of the commercially available TiO₂ nanoparticles. Also considering the possible detrimental effects of TiO₂ nanoparticles on polymeric materials and consequently on physical properties of the paint, chalking and yellowing factors in dried paint samples were evaluated.