Epoxy Cationic Polymerization Under Soft Irradiations (Sunlight, Household Bulbs): The Interest of the Silyl Radical Chemistry

With the existing demand for green technologies, the development of photoinitiating systems for polymerization reactions under air and upon soft irradiation conditions (fluorescence bulbs, sunlight ...) is highly worthwhile. The recently developed silyl radical chemistry is presented here for the free radical promoted cationic polymerization (FRPCP) of different epoxy monomers such as (3,4-epoxycyclohexane) methyl 3,4-epoxy cyclohexylcarboxylate and renewable monomers (epoxidized soybean oil and limonene dioxide) under sunlight and fluorescence bulb or LED lamp exposures. The photopolymerization ability of various photoinitiating systems, the polymerization profiles and the mechanisms (investigated by ESR and Laser Flash Photolysis experiments) will be presented. Some of these systems are also efficient under xenon lamp or laser diodes or can be used in free radical photopolymerization. This work opens up new opportunities for the design of efficient and reactive systems.