Recent advances on coumarin-based photoinitiators of polymerization

Abstract

During the past decades, a breakthrough has been obtained in the development of photoinitiators activable under low light intensity and in the visible range. In the search for new structures, biosourced or bioinspired molecules have been examined as potential candidates for photoinitiation. In this field, coumarins that can be found in numerous flowers, fruits, vegetables and plant species were determined as highly efficient photoinitiators of polymerization. Especially, these structures were determined as acting as efficiency photoinitiators in Type I and Type II initiating systems. In this review, an overview of the recent development on visible light coumarin-based photoinitiators of polymerization is provided. To evidence the interest of these structures, comparisons with reference photoinitiating systems will be provided.

Recent advances on carbazole-based oxime esters as photoinitiators of polymerization

“…Carbazoles and coumarins have been extensively used for the design of Type II photoinitiators. [60,194] Their combination for the design of Type I photoinitiators was thus logical, what was done by Joyeux and coworkers. [277] Four coumarin-carbazole fused structures were designed, bearing an acetyl or a benzoyl group as functionalizing agents of oximes (See Figure 35).…”

Natural and Naturally Derived Photoinitiating Systems for Light-Based 3D Printing

“…Their use in photopolymerization has been widely reported by Dumur and coworkers. 62,63,64 Coumarins are flavonoid type of secondary metabolites present in (green) plants and have been intensively studied due to promising antioxidant, and anti-cancer properties. 65 Moreover, coumarins have been used in sensing, detecting or fluorescence applications.…”

Fused carbazole–coumarin–ketone dyes: high performance and photobleachable photoinitiators in free radical photopolymerization for deep photocuring under visible LED light irradiation

“…A common method for red-shifting absorption is to modify structures through molecular engineering approaches, such as introducing chromophores and large conjugated structures, including carbazole, [25][26][27][28] stilbene, [29][30][31] pyrazoline, 32,33 and coumarin. [34][35][36][37] However, these visible LED PIs have limited applications. Such molecules usually have strong light absorption properties in the visible-light region.…”