Ultrafast Epoxy-Amine Photopolyaddition

A new generation of light-induced production of polymeric materials is presented here. In detail, we propose to use photoacidic catalysis during the well-known epoxy-amine poly addition reaction: it is now referred to as epoxy-amine photo- polyaddition. Soft irradiation (405 nm visible light, 150-450 mW/cm(2)) of a photosensitizer/iodonium salt system leads to the production of superacids (e.g., H+, PF6-) that spectacularly enhance state-of-the-art epoxy-amine polyaddition kinetics: <3 min is necessary to obtain full conversion when >3 h is required to complete the reaction without light. Also, photoactivation greatly enhances final epoxy and amine conversions which resulted in increases (+15 degrees C) of the glass transition temperature of the final 3D polymer networks. This work clearly shows the extremely versatile applications for epoxy-amine photopolyaddition: thin layers (40 mu m), thick layers (up to 2.5 cm), and composites (45 wt % fillers). This work paves the path toward ultrafast production of epoxy-amine composites and adhesives.