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

摘要

Considerable work has been published on oxygen inhibition and ways of overcoming it. Very low viscosity or thin films suffer fast re-oxygenation during the curing process, resulting in reduced monomer conversion, whereas highly viscous or thick film samples re-oxygenate very slowly and the photopolymerisation remains efficient. Amines are well-known co-initiators that have good reactivity towards excited photoinitiators; aminoalkyl radicals react well with acrylate double bonds, but they cannot significandy reduce oxygen inhibition. Silyl radicals, on the other hand, are highly efficient initiating radicals in aerated conditions, but characterised by relatively low hydrogen abstraction rate constants.