10.1007/s11164-014-1859-3
The research investigates the photochemical behavior of commercial TiO2 pigments in aromatic polyurethane coatings by studying the photodegradation of dimethyl toluene-2,4-dicarbamate (2,4-TDC) in a non-aqueous solution. The study finds that rutile TiO2 pigment has better UV-shielding ability and retards the photodegradation of 2,4-TDC, while anatase TiO2 pigment accelerates the process. The photodegradation mechanism of 2,4-TDC is elucidated through the identification of degradation intermediates and theoretical calculations, involving the addition of hydroxyl radicals and the cleavage of the carbamate side chain. The study concludes that rutile TiO2 can act as a UV stabilizer for polyurethane coatings, whereas anatase TiO2 primarily functions as a photosensitizer, causing more degradation. This research provides valuable insights into the roles of different TiO2 pigments in polyurethane coatings and their potential applications in industry.