Synthesis And Characterization Of Fluotinated Photoinitiator

Photoinitiator is one of most important part of photopolymerizationsystem. Free radical photopolymerization was widely used due to itsrapid polymerization rate. But the existed oxygen inhibition of freeradical photopolymerization limited its application. Oxygen on thesurface could quench radicals which could decrease the conversion andmade uncured top layer. Although increasing light intensity orconcentration of photoinitiator could overcome oxygen inhibition, highlight intensity and concentration would lead light shielding and increasevolume shrinkage. In this study, a simple and effective method was usedto overcome oxygen inhibition. Fluorine atoms were introduced totraditional photoinitiator, which made photoinitiator move to the surfacedue to the low surface energy of fluorine. Most of photoinitiator gatheredon the surface and could be consumed by oxygen and a little ofphotoinitiator in the bulk could initiate monomer efficiently.The content and conclusions are described as below:1. The synthesized fluorinated photoinitiator had good photochemical activity and produced radicals effectively, which lead a high doublebond conversion.2. Fluorinated photoinitiator had excellent migratory in both solvent andmonomer. It could move to the surface in a short time.3. Compared to traditional photoinitiator, fluorinated photoinitiator couldovercome oxygen inhibition without any co-initiators or additives.4. Fluorinated photoinitiator could be used to prepare gradient polymer.5. Fluorinated photoinitiator could be used as secondary polymerization.Because most of photoinitiator moved to the surface and some of themwere not initiated, it could still produce radicals to initiate monomer.Secondary polymerization could be used to modify surface propertiesof materials.