Progresses on Sensitization of Cationic Photoinitiators

Abstract

The curing rate and quantum efficiency of cationic photoinitiators are relatively low because the UV absorption of the photoinitiators ranges from 250 nm to 300 nm normally and does not match with the wavelength of light from UV light sources.To make the absorption red-shift,many efforts have been devoted onto the photosensitization of the photoinitiators.The achievements on the sensitization of the cationic photoinitiators have been summarized here.The sensitization is mainly based on the mechanisms as energy transfer,oxidation of free radical,electron transfer via exciplexes and addition fragmentation reaction.The methods adopted for the sensitization include adding photosensitizer,expanding molecular conjugation and attaching chromophore.The development of the photoinitiators and photosensitizers has been outlined and the applications of novel cationic photoinitiators and photosensitizers have been forecasted.