Naphthoylenebenzimidazolone dyes as one-component photoinitiators

摘要

The appropriate substituents have been added to a 7H-benzimidazo[2,1-a]benz[de]isoquinolin-7-one skeleton in order to obtain a one-component initiator system. The absorption, fluorescence, and electrochemical properties of these naphthoylenebenzimidazolone dyes and their usefulness as visible light initiators of free radical polymerisation of trimethylolpropane triacrylate were examined. The initiation efficiency of these dyes was compared with that of the parent 7H-benzimidazo[2,1-a]benz[de]isoquinolin-7-one in the presence of a coinitiator. Results show that these bifunctional dyes are able to initiate polymerisation without an additional coinitiator. Photopolymerisation studies and the relationship between the rate of polymerisation and the free energy change for electron transfer revealed that, depending on the concentration, initiating radicals are generated via intra- and intermolecular electron transfer.