Novel Photoinitiators Based on Benzophenone‐Triphenylamine Hybrid Structure for LED Photopolymerization

• Published in: Macromolecular rapid communications. Vol. 41; no. 23; pp. e2000460 - n/a
• Main Authors: Liu, Shaohui, Brunel, Damien, Sun, Ke, Zhang, Yijun, Chen, Hong, Xiao, Pu, Dumur, Frédéric, Lalevée, Jacques
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.12.2020; Wiley-VCH Verlag
• Subjects: 3-D printers; 3D printing; Benzophenone; Chemical Sciences; Free radical polymerization; Free radicals; Hybrid structures; Industrial applications; Irradiation; Light emitting diodes; Molecular weight; photoinitiator; Photoinitiators; Photopolymerization; Polyimide resins; Polymers; Radiation; Three dimensional composites; Three dimensional printing; triphenylamine; benzophenone; triphenylamine; photoinitiator; 3D printing
• ISSN: 1022-1336; 1521-3927; 1521-3927
• DOI: 10.1002/marc.202000460

In this study, a new generation of photoinitiator (PI) based on hybrid structures combining benzophenone and triphenylamine is proposed. Remarkably, these photoinitiators (noted monofunctional benzophenone‐triphenylamine (MBP‐TPA) and trifunctional benzophenone‐triphenylamine (TBP‐TPA)) are designed and developed for the photopolymerization under light‐emitting diodes (LEDs). Benzoyl substituents connected with triphenylamine moiety contribute to the excellent absorption properties which results in both high final conversions and polymerization rates in free radical photopolymerization (FRP). Remarkably, TBP‐TPA owning trifunctional benzophenone group exhibits a better Type II PI behavior than well‐known 2‐isopropylthioxanthone for photopolymerization under LED@365 and 405 nm irradiation. FRP and cationic photopolymerization of TBP‐TPA‐based systems are applied on 3D printing experiments, and good profiles of the 3D patterns are observed. The high molecular weight of TBP‐TPA associated with it trifunctional character can also be very interesting for a better migration stability of PIs that is a huge challenge. The development of this new generation of photoinitiators based on benzophenone hybrid structures is a real breakthrough. It reveals that the novel versatile photoinitiators based on benzophenone‐triphenylamine hybrid structures have great potentials for future industrial applications (e.g., 3D printing, composites, etc.). Because of the benzophenone‐triphenylamine hybrid structure, excellent light absorption properties are achieved for trifunctional benzophenone‐triphenylamine (TBP‐TPA) and the benzophenone moieties contribute to the Type II H‐ion behavior well. Using TBP‐TPA‐based photoinitiating systems in both FRP and cationic photopolymerization, 3D patterns with high spatial resolution can be obtained.