Breaking Boundaries of Photoinitiators: New Ways to Improve the Reactivity of Radical Polymerization

In this paper, we investigate different ways to increase the reactivity of Type I or Type II photoinitiators by introducing new latent reactive additives leading to additional initiating radicals, promoting singlet-singlet resonance energy transfer of Type I photoinitiators, overcoming diffusional limit in Type II photoinitiating system by pre-associating ion-pairs, or leading to additional initiating radicals and concomitant dye regeneration. The principles underlying these methods are exposed, and an example system is presented for each of these concepts. It is shown that high photopolymerization rates can be achieved even at very low light irradiances.