Synthesis And Application Of Cationic Photoinitiators Of Diaryliodonium Salts

The UV curing process is regarded as a "Green Technology"and has been revealed great vitality in our life with environmental friendliness, economic energy, and economy. However, UV curing always suffers from oxygen inhibition. In recent years, work in overseas laboratory has centered on the synthesis of photoinitiators for cationic photopolymerizations, which were not inhibited by oxygen, in our country the work on this was so little that the cationic photoinitiators were not commercial at all, the price of which was always very high and mostly dependent on import. In this thesis the synthesis of diaryliodonium salts and capability of photopolymerization were researched, and the work for the cationic photoinitiators made in China were attempted further. Iodonium salts were the most important cationic photoinitiators with thermal stability, efficient photopolymerization. In this thesis six classes of diaryliodonium salts were synthesized, in which two classes were new: 4,4′-diacetamidodipheny-liodonium hexafluorophosphate, 3,3′-nitrophenyliodonium hexafluorophosphate. As a key step of the synthesis, the 4,4′-diacetamidodiphenyliodonium hexafluo-rophosphate reaction was researched. While the optimal operation variables were described through orthogonal experiment: when the mole of acetanilide and potassium iodate was 2.2:1.0, 15ml acetic acid at room temperature(25℃), a yield of 47.6﹪was obtained. In this thesis, the effect of cationic structure on photodecomposition of various diaryliodonium salts were discussed, did the spectral sensitivity of the onium salts initiators. When electron-attracting groups or electron-donor groups were introduced, ultraviolet spectra of diaryliodonium salts would expend clearly, of which polymerization was improved greatly. In this thesis, six classes of diaryliodonium salts were researched at the same conditions. First, different cations in the diaryliodonium salts but which were containing the same anion; Second, different anion but which were containing same cations, comparing the photopolymerization and UV curing of these initiators, the structure of diaryliodonium salts and its photopolymerization capacity were discussed. The six classes of diaryliodonium salts were tested by Elementary analysis, Infrared spectrogram, Mass spectrogram, 1H Nuclear magnetic resonance spectro-gram and Ultraviolet spectrogram, etc. With the analysis and discussion of their photoini-tiability, it was indicated that the longest λmax is about 280nm. Solubility with monomers was good, of which the polymerizations of four iodonium salts with BF4-or PF6-are excellent. Thereinto, 4,4′-diacetamidodiphenyliodonium hexafluoro-phosphate and 3,3′-nitrophenyliodonium hexafluorophosphate, especially 4,4′-diace-tamidodiphenyliodonium hexafluorophosphate was the most efficient and had excell-ent use value.