Copolymeric dendritic macrophotoinitiators

Three kinds of copolymeric dendritic macrophotoinitiator DAB-4-TX-OC, DAB-16-TX-OC and DAB-64-TX-OC were synthesized by introducing thioxanthone (TX) and octene (OC) moieties into the periphery of dendrimer poly(propylene imine) (PPI), in order to get photoinitiators systems of high performance. The maximum of absorption (λmax) red-shifted slightly, and the fluorescence emission intensity and the lifetime of the triplet state for TX decreased, with the PPI's generation. Photopolymerization of methyl methacrylate (MMA) and trimethylolpropane triacrylate (TMPTA) initiated by these copolymeric dendritic photoinitiators shows that different photoinitiators exhibit different behaviors towards different monomers: DAB-64-TX-OC is the most efficient for MMA, and DAB-16-TX-OC is the most efficient for TMPTA.