Carbazole derivatives as photosensitizers in cationic photopolymerization of clear and pigmented coatings

The synthesis of some carbazole compounds containing vinyl ether, epoxy or hydroxy groups is reported. They are used as photosensitizers in cationic photopolymerization of vinyl ether and epoxy systems. In clear coatings an increase of the rate of photopolymerization was observed, the most active compound being 1,3-di(carbazol-9-yl)propanol-2. The same behaviour was observed in photosensitized pigmented coatings containing TiO2. An increase of Tg of cured films was observed in the presence of the photosensitizer; also an increase of hardness and solvent resistance was evidenced.