Thioxanthone-ethylcarbazole as a soluble visible light photoinitiator for free radical and free radical promoted cationic polymerizations

摘要

Thioxanthone derivatives are widely used type II photoinitiators due to their light absorption characteristics in the near UV region. However, they have a number of disadvantages including their need for hydrogen donors, low solubility and low sensitivity in the visible region. In high concentrations they have odour, toxicity and migration problems and can decrease the pendulum hardness of the cured film. There are a number of approaches aimed at solving these problems listed in the introduction.