Synthesis And Characterization Of Functional Free Radical Photoinitiator

Photopolymerization technology has been rapidly developed in recent decades and has become an important part of the national production and life. Free radical photopolymerization was the most widely used technology in photopolymerization for its fast polymerization rate and its widely applicability. However, the existed oxygen inhibition and volume shrinkage of free radical photopolymerization limited its application. Represented by2959, the a-hydroxy ketone radical photoinitiators, when radiated by the UV light would split into two kinds of free radical. But there existed controversy about which radical is more active. In this study, an effective but simple method was used to introduce the fluorinated groups and silane coupling agent into the traditional photoinitiator, and prepared two free radical photoinitiator named F-2959and F-2959-Si. The fluoride groups would lead benzoyl radical migrate to the surface of solution because of their low surface energy and low surface tension, while the other free radical is fixed to the substrate surface by silane coupling agent. After the polymerization, the polymer was studied to demonstrate the activity differences between the two free radicals.The content and conclusions are described as below:1. The photoinitiators F-2959and F-2959-Si were synthesed.2. The fluorinated photoinitiator named F-2959had good photochemical activity, which could initiate the free radical photopolymerization. And the fluorinated photoinitiator had excellent migratory in solvents.3. Compared with traditional photoinitiators, fluorinated photoinitiator F-2959had the ability to overcome oxygen inhibition. 4. By grafting photoinitiator F-2959-Si to a substrate, the activity differences between benzoyl radicals and hydroxyl free radical could be determined indirectly. This was because the fluorinated groups lead benzoyl radical migrate to the surface of solution while the hydroxyl free radical was fixed to the substrate surface. Study of the polymers could help to determine that benzoyl radical was more active compared with hydroxyl radical.