FWF - Kreuz-konjugierte Photo - Cross-conjugated Photoinitiators

Photoinitiated radical polymerization is an efficient and environmentally friendly tool to convert monomers such as acrylates within the fraction of a second into solid polymers. The photoinitiator (PI) is the core part of the formulation; light is converted to chemically reactive intermediates. Recently, we have found that a planar crossconjugated photoinitiator 1,5-diphenyl-1,4-pentadiyn-3-one (1) gives a significant impulse for new concepts in radical photoinitiators. The new photoinitiator provides several advantages compared to the state of the art. Beside simple one pot synthesis, the PI is characterized by a strong UV absorption due to the cross-conjugation tailing out to the visible range of the spectrum. High photoinitiation activity using extremely low initiator concentration (0.05wt%) and no need for amine based coinitiators are the main advantages. Furthermore this class of compound is characterized by low toxicity, excellent solubility and storage stability in any kind of resins. To extend this new and promising field of photoinitiation, fundamental research is necessary to understand the mode of initiation. By exploring the photochemistry and photophysics (laser flash photolysis) of this compound, especially by identification of the initiating species (Photo-CIDNP) and photoproducts, optimization of the diyone based photoinitiator and expansion of this concept to other photoinitiating systems should be possible. Furthermore, good photoinitiation activity for a new and promising field of photopolymerization, two photon absorption (TPA) photopolymerization, could be expected by selected D--A--D derivatives. Due to the low toxicity of PI 1 (LD50>1g/kg) biocompatibility tests and screening as photoinitiator for dental applications or silicone release coatings should be done by external partners