Unimolecular Type Ⅱ radical photoinitiators(PIs) have received significant attention in photocuring owing to the fact that they improve the sustainability of the overall process compared with traditional Type Ⅱ radi...Unimolecular Type Ⅱ radical photoinitiators(PIs) have received significant attention in photocuring owing to the fact that they improve the sustainability of the overall process compared with traditional Type Ⅱ radical photoinitiators. However, the photopolymerization efficiency of unimolecular Type Ⅱ radical photoinitiators is hindered by their short excitation wavelengths,poor photon capture abilities, and inefficient photobleaching performance. Herein, we report a coumarin-based self-sufficient initiator(C-NA), which is designed by integrating “hydrogen donor” and “hydrogen acceptor” into the coumarin framework and used for single-component visible light curing. C-NA exhibits a visible light absorbance and high molar extinction coefficient and is completely photobleached under the irradiation of 405 nm light-emitting diodes(LEDs). The formation of free radicals arises from the transfer of hydrogen from the diethylamino group to the coumarin framework, together with a highly efficient photodegradation process of C-NA. Finally, C-NA was successfully applied to prepare a transparent film material. Therefore,C-NA offers new insights into the design of promising unimolecular Type Ⅱ radical photoinitiators for photocuring.展开更多
基金supported by the National Natural Science Foundation of China (21925802, 22338005)the Liaoning Binhai Laboratory (LBLB-2023-03)the Fundamental Research Funds for the Central Universities (DUT22LAB601)。
文摘Unimolecular Type Ⅱ radical photoinitiators(PIs) have received significant attention in photocuring owing to the fact that they improve the sustainability of the overall process compared with traditional Type Ⅱ radical photoinitiators. However, the photopolymerization efficiency of unimolecular Type Ⅱ radical photoinitiators is hindered by their short excitation wavelengths,poor photon capture abilities, and inefficient photobleaching performance. Herein, we report a coumarin-based self-sufficient initiator(C-NA), which is designed by integrating “hydrogen donor” and “hydrogen acceptor” into the coumarin framework and used for single-component visible light curing. C-NA exhibits a visible light absorbance and high molar extinction coefficient and is completely photobleached under the irradiation of 405 nm light-emitting diodes(LEDs). The formation of free radicals arises from the transfer of hydrogen from the diethylamino group to the coumarin framework, together with a highly efficient photodegradation process of C-NA. Finally, C-NA was successfully applied to prepare a transparent film material. Therefore,C-NA offers new insights into the design of promising unimolecular Type Ⅱ radical photoinitiators for photocuring.
