The Sythesis Ang Application Of Acylphosphine Oxide Photoinitiators

Recently, synthesis and application study of acylphosphine oxide photoinitiators have been focused in the LED light curing field, because of their good light initial properties..In this dissertation, 16 a-hydroxybenzyldiphenylphosphine oxide compounds were synthesized by reaction of diphenylphosphine oxide (DPO) and aromatic aldehydes with different structures. The effect of various catalytic oxidation systems on the oxidation of the intermediates was investigated, and six acylphosphine oxide compounds were synthesized successfully using active manganese dioxide as the oxidant. The structures of the target compounds were characterized by NMR, MS and IR. It was found that the substituent effects are bound up with the stability of photoinitiators: electron-donating groups which are bulky and have lone pair electrons could help to stabilize the target compounds. Therefore,4-diethylaminobenzoyldiphenylphosphine oxide (DEAPO) and(3-benzoyl-2,4,6-trimethylbenzoyl)diphenylphosphine oxide (BzTPO) have good storage stability.Through the research on spectral properties of target product, it was found: compared to commercial product of TPO, the absorbance wavelength of DEAPO has obviously redshift and possesses ultra-high molar absorption coefficient. The UV-Vis absorption curve of BzTPO is similar to TPO, but the molar absorption coefficient at longer wavelength is a bit lower than TPO.The light curing efficiency of DEAPO and BzTPO compared with TPO or Irgacure 819 was investigated by curing of trimethylolporpane triacrylate (TMPTA) under LED light source with the central wavelength at 385 (LED@385) and 420 nm (LED@420), respectively. The results showed that with the increase of light intensity and photoinitiator content, the curing efficiency of the photoinitiating system become better and better. Photoinitiating system with DEAPO as photoinitiator has great advantage on curing efficiency compared to traditional photoinitiator TPO and Irgacure 819 under two-LED light sources. In the case of BzTPO, the curing efficiency of BzTPO at LED@385 is comparable but a bit lower than TPO, while that at LED@420 is a bit higher than TPO. Moreover, DEAPO has more significant advantages when combining with DETX than traditional two-component DETX/EDAB on curing efficiency,which could be used as photosensitizer for the reason that it possesses a high molar absorption efficient.