Methylene blue-clay nano-pigment as a new photosensitizer for preparing three-component photoinitiating systems with high thermal stability

Abstract The use of three-component photoinitiating systems (PISs), as a major type of visible light photoinitiating systems, are considerably growing in different industries. However, their low storage and thermal stability could be an obstacle that prevents the fast growth of this type of PIS. In this study, a methylene blue nano-pigment was synthesized, characterized and used as a new photosensitizer (PS) in a three-component PIS. The prepared nano-pigment was characterized by using CHNS, TGA, XRD and TEM techniques. The photopolymerization characteristics of this new PIS was studied by using RT-FTIR. In addition, the thermal stability of the new three-component PIS was investigated by using DSC analysis. Moreover, mechanical properties of SR349 acrylate monomer which was cured in the presence of this PIS were evaluated by using DMTA technique. In addition, the morphology of the nanoparticles in the cured system was analyzed by using TEM and XRD. The results showed that the proposed PIS could be efficiently used for the free radical photopolymerization of acrylate monomers and oligomers. It was also demonstrated that the thermal stability of the prepared PIS was remarkably better than that for a reference PIS. Photocurable systems which were prepared by using this new three-component PIS were found to be thermally stable up to 100 °C. Finally, it was revealed that the cured system in the presence of the new three-component PIS had a very good stiffness and relatively high glass transition temperature.