新型的香豆素染料/碘鎓盐光敏引发系统的研究

在实际应用中，大部分光敏引发系统只对紫外光敏感．近年来，随着Ａｒ＋（４８８ｎｍ）、ＹＡＧ（５３２ｎｍ）以及ＨｅＮｅ（６３３ｎｍ）激光技术的不断发展，高效的长波长光敏引发体系成为研究的重点．其中之一的方法是使引发剂直接感可见光，然而取得的结果并不显著．所以染料敏化又一次成为焦点．其中最重要的技术是使光敏引发系统的吸收波长移向长波长，并且具有高的灵敏度．大部分的光敏引发系统是由二个或三个组分组成，长波长的光引发聚合是通过以下两种不同过程得到实现［１］：（１）光敏系统直接吸收光并激发，（２）光引发系…

STUDY OF A NOVEL PHOTOSENSITIVE INITIATING SYSTEM OF COUMARIN DYE/IODONIUM SALT

The photosensitive initiating system composed of 7 diethylamino 3 (2’ N methylbenzimidazolyl)coumarin dye (DBC) as sensitizer and diphenyliodonium hexafluorophosphate (DIH) as initiator,can be used to initiate the polymerization of methyl methacrylate (MMA) in visible light.When exposed to visible light,coumarin dye/iodonium salt undergoes quick electron transfer from DBC to DIH and free radicals are produced.The visible light photoinduced reaction between DBC and DIH is mainly through the excited singlet state of DBC and thus it is little sensitive to O 2.The fluorescence of DBC can be quenched efficiently by DIH and the change is in accord with Stern Volmer equation and the quench constant K q can reach 10 12 M -1 S -1 .The influence of concentration of DBC on the polymerization rate of MMA shows that coumarin free radical act mainly as chain terminator in polymerization and has a stronger tendency to terminate the chain reaction.