Photoinitiators with functional groups, 8 - Benzophenone with covalently bound phenylglycine

Bimolecular type-II photoinitiators for radical photopolymerization suffer from a diffusion-controlled limitation of reactivity and from deactivation by back electron transfer. Here, a very efficient concept to increase the photoinitiator activity by the covalent binding of phenylglycine to benzophenone using a methylene spacer is presented. Photo-DSC experiments proved that the rate of polymerization can be tripled in comparison to a physical mixture of the components or an industrially applied system with triethanolamine as coinitiator.