Cyclopolymerizable and cyclopolymeric photoinitiators from diallyl amine and α-hydroxy ketones

Two novel cyclopolymerizable photoinitiators (DAA-I2959 and DAA-I184) are synthesized by attachment of diallyl amine (DAA) to 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure 2959 or I2959) and 1-hydroxycyclohexyl phenyl ketone (Irgacure 184 or I184); for free radical polymerization of (meth)acrylates. The copolymerization of DAA-I2959 with diallyldimethylammonium chloride (DADMAC) in the presence of hydrochloric acid gives a novel water soluble linear polymeric photoinitiator (PPI), p-DADMAC-co-DAA-I2959-QS (M-n = 40 000-60 000 D) with five-membered pyrrolidine rings in the main chain (first PI with a cyclic backbone in the literature). DAA-I2959, its copolymer and DAA-I184 have strong absorbances at 272, 266 and 244 nm (epsilon similar to 14 705, effectively 8000 and 11 625), respectively, in methanol. These PIs can successfully initiate the photopolymerization of poly(ethylene glycol) diacrylate (PEGDA, M-n = 575 D) or 2-hydroxyethyl methacrylate (HEMA); DAA-I2959 exhibits a photoinitiating ability similar to I2959 and can also be used as a hydrogen donor for a Type II photoinitiating system. DAA-I184 shows much slower kinetics compared to I184. DAA-I2959 and p-DADMAC-co-DAA-I2959-QS exhibit fairly good migration stability (similar to 3.5 and 6.8 times higher) compared to I2959.

Automated summary

Two novel cyclopolymerizable photoinitiators (DAA-I2959 and DAA-I184) were synthesized for free radical polymerization. DAA-I2959 exhibits similar photoinitiating ability to I2959 and can also act as a hydrogen donor for a Type II photoinitiating system.