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1,2-Diketones as photoinitiators of both cationic and free-radical photopolymerization under UV (392 nm) or Blue (455 nm) LEDs |
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| Authors: | Jing Zhang Shuhui Wang Jacques Lalevée Fabrice Morlet-Savary Elizabeth S-H Lam Bernadette Graff Jing Liu Feiyue Xing Pu Xiao |
| Institution: | 1. Research School of Chemistry, Australian National University, Canberra, 2601 Acton, Australia
Department of Chemical Engineering, Monash University, Clayton, 3800 Victoria, Australia;2. Institute of Tissue Transplantation and Immunology, Department of Immunobiology, Jinan University, Guangzhou, 510632 China Key Laboratory of Functional Protein Research of Guangdong, Higher Education Institutes, Jinan University, Guangzhou, China;3. Institut de Science des Matériaux de Mulhouse IS2M, UMR CNRS 7361, ENSCMu-UHA, 15 Rue Jean Starcky, 68057 Mulhouse Cedex, France;4. Institut de Science des Matériaux de Mulhouse IS2M, UMR CNRS 7361, ENSCMu-UHA, 15 Rue Jean Starcky, 68057 Mulhouse Cedex, France Université de Strasbourg, Strasbourg, France;5. Research School of Chemistry, Australian National University, Canberra, 2601 Acton, Australia;6. School of Stomatology, Jinan University, Guangzhou, 510632 China;7. Institute of Tissue Transplantation and Immunology, Department of Immunobiology, Jinan University, Guangzhou, 510632 China |
| Abstract: | The photoinitiation abilities of three 1,2-diketones i.e., acenaphthenequinone ( ANPQ ), aceanthrenequinone ( AATQ ), and 9,10-phenanthrenequinone ( PANQ )]-based photoinitiating systems PISs, with additives such as iodonium salt, N-vinylcarbazole (NVK), tertiary amine, and phenacyl bromide (R-Br)] for cationic photopolymerization and free-radical photopolymerization under the irradiation of ultraviolet (UV; 392 nm) or blue (455 nm) light-emitting diode (LED) bulb are investigated. All 1,2-diketones studied exhibit ground state absorption that match with the emission spectra of UV (392 nm) or blue LED (455 nm) better than that of the well-known blue-light-sensitive photoinitiator camphorquinone (CQ). In particular, AATQ /iodonium salt/NVK can show high photoinitiating ability (with epoxide conversion yield >70%) under the UV light irradiation due to the effect of NVK. In addition, 1,2-diketone/iodonium salt (and optional NVK) systems are capable of initiating free-radical photopolymerization of methacrylates, with conversions of 50–58%. Furthermore, some 1,2-diketone/tertiary amine (and optional R-Br) combinations are found to demonstrate high efficiency to initiate free-radical photopolymerization, and 71% of methacrylate conversion can be achieved with PANQ /tertiary amine/R-Br PIS. Some 1,2-ketone-based PISs can even exhibit higher efficiency than the CQ-based systems. The photochemical mechanism of the radical generation from the 1,2-diketone-based PISs is investigated and found to be consistent with the related photopolymerization efficiency. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 792–802 |
| Keywords: | 1 2-diketone blue LED cationic photopolymerization photoinitiator photoinitiating system free-radical photopolymerization UV LED |