Novel Triphenylamine Substituted Organoboron Derivatives for Free Radical Photopolymerization Under Visible LEDs Irradiation and Application in 3D Printing

In terms of photopolymerization, a crucial role in the photoinitiation step is played by the photoinitiators that can generate the initiating species by absorbing suitable lights. Nowadays, the study for visible light‐sensitive photoinitiators is appealing more and more research interest. In this work, two kinds of difluoroboronated pyridylhydrozone derivatives substituted by triphenylamine moiety were carefully designed and proposed as the potential photoinitiators under visible lights irradiation. These two organoboron dyes displayed a broad light absorption property in the ultraviolet (UV) and visible range. Very interestingly, in combination with amine and iodonium salt to form three‐component systems, a tiny amount of the organic boron photoinitiators could initiate the free radical photopolymerization of acrylate monomers efficiently under the irradiation of violet and blue lights, respectively. Based on experimental characterizations and theoretical calculations, the photochemical reactivity and the underlying chemical mechanism within the photoinitiating systems were investigated in detail. Moreover, the photoinitiation capacity of the reported organic dyes was successfully applied in 3D printing area, and many tridimensional patterns were fabricated, which showed remarkable emission properties.