A Highly Efficient Polymerizable Photoinitiator Comprising Benzophenone, Thio Moieties, and N-Arylmaleimide

A novel, highly efficient, polymerizable, thio-containing photoinitiator, 4-maleimido-4'-thiophenylbenzophenone (MTBP), was synthesized by directly introducing maleimide to benzophenone moieties. Three polymerizable photoinitiators with different location or number of maleimide substituents, together with the bare benzophenone, were chosen to evaluate the photoefficiency of MTBP. Photopolymerization studies indicate that polymerizable photoinitiator with single maleimide substituent directly linking to benzophenone moieties is more efficient for photopolymerization of vinyl monomers than those with indirect or double maleimide substituents. As for the photopolymerization of 1,6-hexanediol diacrylate, MTBP show surprisingly high efficiency, and the final conversion runs up to 95.94%.