NOVEL AND EFFICIENT WATER-SOLUBLE PHOTOINITIATOR FOR POLYMERIZATION

Photopolymerizable compositions are used in increasing areas of applications. Thorough mechanistic studies are being conducted in the field of solution, bulk, or micelle photopolymerization; in this light, the aim of this work is to develop very efficient and practical systems for ultraviolet (UV) curing. The rate of polymerization was measured as a function of the optical density (OD) of the solution (i. e. , the concentration of QC). Its dependence on the incident light intensity (I//o), the monomer concentration (M), and the presence of an additive such as a hydrogen donor (THF) was also studied. QC appears to be a very efficient photoinitiator for vinyl polymerization in micelle. Additional results concerning the quantum yield of polymerization, phi //m, are reported and compared with data obtained for other photoinitiators. As expected one observes a substantial increase of R//p and phi //m when going from benzophenone (BP) to QC (these two compounds have a triplet-state lifetime in the range of a few microseconds in deaerated solution).