High-performance anthrone-based low-migration photoinitiators for low-power photopolymerization

Abstract

In this work, anthrone-based donor-acceptor-donor type photoinitiators (DXD and DTD) were synthesized and introduced into a two-component system with diphenylIodonium hexafluorophosphate (Iod) for radical photopolymerization of acrylic resin monomers. At the photoinitiator concentration of 0.5 wt%, under irradiation with LED@365 nm at the power of 20 mW cm ^{- 2} , the double bond conversion of monomer initiated by DXD, DTD were 63%, 64%, respectively, showing more excellent photoinitiation activities in comparison with that of the commercial photoinitiator (2-isopropylthioxine, ITX) of 52%. DTD and DXD even achieved 75% and 71% conversion rates at lower power (10mW cm ^-2 ), respectively. Moreover, DXD (7%) and DTD (8%) exhibited rather lower mobility than ITX (37%) in light-curable films. Remarkably, triplet states were revealed to have an important effect on photopolymerization. The relevant mechanisms were scientifically understood by means of steady-state photolysis, fluorescence quenching, laser flash photolysis and electron spin resonance spin trapping technologies.