Bifunctional co-initiators: A new strategy for the design of efficient systems in radical photopolymerization reactions under air

Bifunctional co-initiators containing amine and silane groups (silylamines) are proposed for radical photopolymerization in experimental conditions (e.g. low light intensity, low viscosity thin samples, UV and visible light exposure) where a strong deleterious oxygen effect occurs. In the presence of benzophenone, isopropylthioxanthone, camphorquinone, 2,6-diphenyl-4-(4′-dimethylaminophenyl) thiopyrylium tetrafluoroborate, chloro-HABI and cleavable photoinitiators, these compounds show a high reactivity under air, even better than that observed for a reference amine as a hydrogen donor. The associated mechanisms are investigated by laser flash photolysis (LFP) and Kinetic ESR.

Figure optionsDownload as PowerPoint slideHighlights
► New co-initiators for free radical polymerization in aerated conditions are proposed.
► New bifunctional co-initiators containing amine and silane groups (silylamines).
► The amine for efficient initiation process and the silane to overcome the oxygen inhibition.
► Polymerization under visible light or very soft irradiation conditions.
► Chemical mechanisms investigated by ESR experiments.