UV aging of styrene-acrylic polymer SiO2 and TiO2 composites

The photodegradation of coatings based on styrene-acrylic polymer and nanoparticles: hydrophobized silica (40–70 nm) and photoactive titanium dioxide (50–100 nm) was investigated. By the means of FTIR, goniometry, and SEM, it is shown that the use of titanium dioxide provides acceleration of photooxidation processes in comparison with the silica-based system. However, the formation of volatile decomposition products is not accelerated, which leads to the formation of a textured surface with polar polymer residues. Such surfaces have high wettability because of the capillary structure and intrinsic high surface energy. It was confirmed that the addition of nanoparticles reduces the ablation rate to 0.74 µm/h for TiO2 and to 0.85 µm/h for SiO2 due to the UV shielding effect.