N-substituted quinoxalinobenzothiazine/iodonium salt systems as visible photoinitiators for hybrid polymerization
作者:Radosław Podsiadły、Rafał Strzelczyk
DOI:10.1016/j.dyepig.2013.01.021
日期:2013.6
Sensitizers based on the 12-substituted 12H-quinoxalino-[2,3-b][1,4]-benzothiazine skeleton were synthesized and characterized using H-1 NMR spectroscopy, mass spectrometry and elemental analysis. Their electrochemical and spectral properties, including absorption and emission spectra, fluorescence quantum yield and singlet lifetime were also measured. These benzothiazines combine with commercially available diphenyliodonium hexafluorophosphate to create novel visible initiator systems of free radical/cationic hybrid polymerization of glycidyl methacrylate. The efficiency of these initiator systems is discussed on the basis of the free energy change for electron transfer from the benzothiazines to the iodonium compound. During the photopolymerization photobleaching of the benzothiazines was observed; a mechanism to account for this bleaching is proposed. (c) 2013 Elsevier Ltd. All rights reserved.