Phenothiazine-based oxime ester as a photobase generator for thiol-acrylate reactions
Résumé
In this work, a previously designed and synthesized phenothiazine-based oxime ester was investigated as a photobase generator for the formation of thiol-acrylate networks through the polymerization of thiol-acrylate reactions and more appealingly the base-catalyzed thiol-acrylate Michael addition reactions. This system accomplished a complete disappearance and a full conversion of the characteristic acrylate peak within 10 min of irradiation with a light-emitting diode (λ = 405 nm) or within 1 or 2 min of the same irradiation source and 24 hours of heat exposure (T = 60 °C). Photobase generation was evidenced using phenol red as a pH-indicator, enabling to confirm the production of methyl amine (CH3NH2) as initiating species. Photoinitiation mechanism through which base reactive species are produced and the reactions by which the thiolacrylate polymerization proceeds were investigated according to the base detection experiments, the obtained real-time Fourier transform infrared spectroscopy results, and according to the general photochemical base-generation reactions of oxime-esters. Finally, differential scanning calorimetry scans and Shore A and Shore D hardness experiments have been performed on the polymers obtained to examine their thermal properties and surface hardness features.
Domaines
MatériauxOrigine | Fichiers produits par l'(les) auteur(s) |
---|