Xanthene dyes/amine as photoinitiators of radical polymerization: A comparative and photochemical study in aqueous medium
Xanthene dyes/amine as photoinitiators of radical polymerization: A comparative and photochemical study in aqueous medium
复制标题
DOI：
10.1016/j.polymer.2009.04.024
复制
发表时间：
2009-06-19
期刊：
影响因子：
4.6
通讯作者：
Previtali, C. M.
中科院分区：
文献类型：
--
作者：
Encinas, M. V.;Rufs, A. M.;Previtali, C. M.
评价了几种氧杂蒽染料作为水介质中自由基聚合光引发剂的效率。这些结果表明，具有高于0.1的三重态量子产率的染料呈现类似的效率，而与它们的不同化学结构无关。使用激光时间分辨光谱对聚合条件下染料的光物理进行了详细的研究。这些研究表明，活性自由基是染料的激发三重态与胺通过电子转移过程相互作用形成的自由基。尽管如此，光引发效率与三重态量子产率不相关。此外，光物理研究表明，电荷转移中间体的分解的不同途径的量子产率是预测这些光引发剂系统的效率的重要参数。实验测得的活性自由基的形成是很好的相关性从聚合速率计算。氧杂蒽环中重原子的存在增加了三重态量子产率，但降低了活性自由基产率，进而降低了聚合速率。(C)2009爱思唯尔有限公司保留所有权利。
The efficiency of several xanthene dyes as photoinitiators of the free radical polymerization in aqueous medium was evaluated. These results show that dyes with triplet quantum yield higher than 0.1 present similar efficiencies, independently of their different chemical structure. A detailed study of the photophysics of the dyes under the polymerization conditions was carried out using laser time-resolved spectroscopies. These studies show that the active radicals are those which formed in the interaction of excited triplet state of the dye with the amine through an electron transfer process. In spite of this, the photoinitiation efficiency is not correlated with the triplet quantum yield. Also, the photophysics studies show that the quantum yield of the different pathways of the decomposition of the charge transfer intermediate is an important parameter to predict the efficiency of these photoinitiator systems. The experimentally measured active radical formation is well correlated with that calculated from the polymerization rate. The presence of heavy atoms in the xanthene ring increases the triplet quantum yield, but decreases the active radical yield, and then the polymerization rate. (C) 2009 Elsevier Ltd. All rights reserved.