A New Photoinitiator for Laser-Induced Ultrafast Polymerization

A new photoinitiator, 4-phenoxy benzophenone (PBZP), was synthesized and characterized using diphenyl ether and benzoyl chloride as raw material. It can effectively absorb photons of N_2 laser and then initiate the ultrafast crosslinking polymerization of epoxyacrylate resin. The synthetic product was identified with mass spectroscopy and IR spectroscopy. The properties of PBZP were dompared with those of two useful photoinitiators, benzoin ethylether (BEE) and benzophenone (BZP). The characteristics of UV absorbency were analyzed with UV spectroscopy. Kinetics of polymerlization was investigated with FTIR method, and the reaction mechanism of these laser-photoinitiators were discussed. The results show the rate of polymerization of PBZP system reaches 10~6 mol/L.s in the presence of air, being four orders of magnititude larger than the rate gotten with continuous UV light sources. The quantum yield of the former is 3.5 mol/E. All these properties of PBZP are better than those of BEE and BZP.