Derivatives of 1,4‐naphthoquinone as visible‐light‐absorbing one‐component photoinitiators for radical polymerisation

Abstract

Bifunctional visible-light photoinitiators for free radical polymerisation based on a 1,4-naphthoquinone skeleton were synthesised and characterised using proton nuclear magnetic resonance spectroscopy and chemical ionisation mass spectrometry. Their basic spectroscopic properties, such as absorption and lowtemperature phosphorescence spectra, and their red-ox properties were also measured. These initiators contain an appropriate electron/hydrogen donor group in the skeleton and do not require an additional coinitiator for initiation. During irradiation they act both as a triplet photosensitiser and as a hydrogen/electron donor. The ability of each naphthoquinone to act as a photoinitiator strongly depends on its chemical structure. These studies suggest that initiator radicals are generated from the triplet state in an intermolecular electron/hydrogen transfer reaction.

Synthesis and application of dyes derived from benz[cd]indol‐2(1H)‐one as visible‐light‐absorbing polymerisation photoinitiators

“…Thioxanthone [19][20][21][22] and benzophenone [23][24][25][26] and, more recently, novel erythrosine B [27] and naphthoquinone [28] derivatives linked with appropriate groups have been synthesised and applied as initiators for free radical polymerisation. There are very few chromophores that can be used to design onecomponent initiator systems.…”

“…There are very few chromophores that can be used to design onecomponent initiator systems. Thioxanthone [19][20][21][22] and benzophenone [23][24][25][26] and, more recently, novel erythrosine B [27] and naphthoquinone [28] derivatives linked with appropriate groups have been synthesised and applied as initiators for free radical polymerisation.…”

Naphthoylenebenzimidazolone dyes as one‐component photoinitiators

“…Indeed, in some papers NMP is used as coinitiator. The same situation was encountered in previous papers [18,19]. Therefore, we used NMP as a diluted component.…”

“…In the last decade many papers have described the synthesis of initiators. Only thioxanthone [3][4][5][6][7][8][9], benzophenone [10][11][12][13][14][15][16], erythrosine B [17], and, more recently, naphthoquinone [18] and benz[cd]indol-2(1H)-one [19] linked with appropriate groups have been applied as chromophores to obtain one-component initiator systems. There are two different ways to create initiators sensitive to visible radiation.…”

Cationic Photoinitiators for Near UV and Visible LEDs: A Particular Insight into One‐Component Systems

“…ref. [1k],, and the particular use of the LED technology outlined in a recent review . In CP and FRPCP, two‐ and three‐component PISs are currently used (see below).…”