NIR photothermal activation in epoxy/anhydride systems for advanced polymerization

• Photothermal anionic polymerisation of epoxy/anhydride system. • N-Heterocyclic carbene generator as thermolatent initiator. • NIR dyes as local heat induction and reaction influencing compound. • Safer irradiation wavelengths (NIR) for photopolymerization processes. Photopolymerization is an important area of investigation due to its wide industrial applications; however, it generally employs quite energetic UV or near UV light to initiate the formation of the polymer. Even though it is very effective and offers several advantages, numerous drawbacks are also encountered such as low light penetration, harmfulness of wavelengths in the UV range and the use of photoinitiators that can be hazardous to health. In this context, many researchers have focused their interest in improving the spatial localization and the temporal control of the polymerization under safer irradiation wavelengths (NIR). In this work, we have successfully produced polyester thermosets by the reaction of epoxy resins with anhydride in the presence of a thermolatent N -Heterocyclic carbene generator using the NIR photothermal effect of a dye (heater) able to convert low-energetic NIR light into heat.