Résumé : |
Growing interests in cationic photopolymerisation of monomers as a facile, economic and environmentally safe method for preparation of crosslinked polymer coatings, stimulates search for new photoinitiators. Usually, diaryliodonium salts are used in industry as the cationic polymerisation photoinitiators. However, from a practical point of view, the most important feature of the photoinitiators is their optical characteristics, in particuler the range and extent of light absorption. Nowadays, ail of the iodonium photoinitiators used in industry exhibit similar absorption characteristics and absorb UV light in the range of Xmax = 220-280nm. This creates a technological problem, because there are no economical and simultaneously powerful enough light sources that would emit UV light in that range. In the photocurable coatings industry medium pressure mercury lamps are used, which emit most of their energy at about 365nm and only a fraction is emitted in the absorption range of commercial iodonium photoinitiators. Hence, there is a mismatch between the absorption characteristics of the photoinitiators and the emission characteristics of industriel light sources, which lowers the photo-polymerisation rate. In order to solve that problem, we developed several GalOrti (Photo High Technologies Ltd) iodonium photoinitiators. The performance of the GalOrti photoinitiators in cationic photopolymerisation of an example monomer will be presented using the Fluorescence Probe Technology Method. |