Thioxanthone-functionalised 1,6-heptadiene as monomeric photoinitiator
The synthesis of the first photoinitiator (PI) based on thioxanthone (TX) with 1,6-heptadiene structure has been described in a recent study.
This PI (TXdMA) absorbs in the near UV–vis region (435–439 nm; with absorption redshift≈50 nm and ε values comparable to TX).
Photopolymerisation results demonstrate that although TXdMA is not an effective one-component polymerisable photoinitiator, it can successfully initiate photopolymerisation of poly(ethylene glycol) diacrylate (PEGDA, Mn = 250 D) and trimethylolpropane triacrylate (TMPTA) in the presence of bis-(4-tert-butylphenyl)-iodonium hexafluorophosphate (Iod) similar to TX/Iod.
Better migration stability than TX
TXdMA exhibits better migration stability than TX. Absorption, fluorescence, steady state photolysis and cyclic voltammetry experiments are carried out to investigate the photochemical mechanisms.
The study has been published in Progress in Organic Coatings, Volume 128, March 2019.
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