新型感可见光的染料鎓盐光引发体系

本文报道了一种新型感可见光的引发体系-曙红双(二苯基碘鎓盐)(Eo(IPh_2)_2).在基态,这种体系具有良好的热稳定性,而在激发态时能发生离子对内光诱导电子转移反应,导致其发生漂白和碘鎓盐的分解反应,产生具有引发作用的自由基.该体系适用于一般烯类单体的自由基聚合,其中时丙烯酸酯类单体效果最好.在以甲基丙烯酯甲酯(MMA)为单体时,聚合反应速度满足动力学方程:R_p=lEo(IPh_2)_2]~(0.38)MMA],并求得聚合反应的活化能E_c=7.00kcal/mol.氧在Eo(IPh_2)_2光敏引发聚合中,既起自由基聚合阻聚剂的作用,又起引发剂三重态猝灭剂作用

A NOVEL VISIBLE-LIGHT SENSITIVE DYE-ONIUM SALT PHOTOINITIATOR

A new visible-light sensitive photoinitiator, bis (diphenyl-iodonium) salt of eosin, is reported. This system has good thermal stabi ity in ground state. When excited, it can undergo intra-ion-pair electron transfer, leading to the bleaching of the dye and the decomposition of the onium salt. The later results in the formation of initiating radical species. This system can be used as a photoinitiator in radical polymerization of conventional vinyl monomers, especially for acrylates. When methyl methacrylate (MMA) is chosen as the monomer, the polymerization satisfeis the following kinetic equation:Rp=kpE0(IPh2)2]0.38MMA]The activation energy of polymerization was obtained to be Ea = 7.00kcal/mol. In the polymerization system, oxygen acted not only as the inhibitor of polymerization, but also as the quencher of the triplet of the initiator.