Amphiphilic polymeric Michler's ketone (MK) photoinitiators (APMKs) containing PEO chain and coinitiator amine

Abstract

A series of amphiphilic polymeric Michler's ketone (MK) photoinitiators (APMKs) were synthesized by incorporating PEO short chain, MK moiety, and coinitiator amine into the same polymeric chain. APMKs possess good amphiphilic ability and become water‐soluble when the molar ratio of MK(pipaz)2/PEO/piperazine is 2:3:1. UV–Vis measurement shows that APMKs possess the same characteristic absorption to MK derivatives. The photopolymerization of three monomers with different functionality and hydrophilicity, polyethylene glycol diacrylate (PEGDA), phenoxy ethyl acrylate (AMP‐10G), and 2,2‐bis[4‐(acryloxypolyethoxy)phenyl]propane (A‐BPE‐10) initiated by APMKs was investigated by photodifferential scanning (photo‐DSC). The results show that APMKs can photoinitiate the polymerization of hydrophilic and hydrophobic monomers efficiently. As for photopolymerization of water‐soluble PEGDA, the final conversion is higher than 94%. Therefore, APMKs will be expected to find potential in many fields. Copyright © 2009 John Wiley & Sons, Ltd.

Thioxanthone‐Based Hydrophilic Visible Photoinitiators for Radical Polymerization

“…One is the substituted amines, the other is the hydrogen on polyether chains. [ 32,55,64,[84][85][86] During the initial irradiation period, the substituted amines in TX-MPEGs were preferentially used as hydrogen donor and produced the active free radicals. Since the TX-MPEGs were amphiphilic and formed micelles in water, this procedure for free radical production would be carried out in micelles.…”

“…Water‐soluble compounds such as xanthene dyes/amine,phenoxazine dyes/amine, synthetic dyes derived from thioxanthone (TX) and safranine‐T, transition‐metal complexes, 4,5‐di‐iodosuccinylfluorescein/methyl blue, naphthalimide derivatives/2,6‐di‐ O ‐Me‐β‐cyclodextrin complex, carboxylated camphorquinone, hydroxyl alkyl phenyl ketones, phenacylpyridinium oxalate, and bis(mesitoyl)phosphinic acid were used as sensitizers for the photocrosslinking of water‐soluble photopolymerization systems. The introduction of water solubilizing groups onto a conventional photoinitiators, such as polysilane, hydroxyalkylphenone, Michler's ketone, benzophenone, anthraquinone, xanthene, α‐diketones, aliphatic ketones, riboflavin, 2‐benzyl‐2‐(dimethylamino)‐1‐(4‐morpholinophenyl)‐1‐butanone, and TX is a trend to obtain water‐soluble photoinitiators.…”

“…Among them, TX-MPEG550 has been illustrated as the best hydrophilic visible photoinitiator in the presence of hydrogen donors and would have great potential applications in waterborne visible photocuring systems after carefully investigating the photopolymerization behavior of TX-MPEGs in different conditions. solubilizing groups onto a conventional photoinitiators, such as polysilane, [ 28,29 ] hydroxyalkylphenone, [ 30,31 ] Michler's ketone, [ 32 ] benzophenone, [ 33 ] anthraquinone, [ 34 ] xanthene, [ 35 ] α-diketones, [ 36,37 ] aliphatic ketones, [ 38 ] ribofl avin, [ 39 ] 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, [ 40 ] and TX [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] is a trend to obtain water-soluble photoinitiators.Among them, TX derivatives are one of the most investigated chromophores as water-soluble photoinitiators not only because of their high photoinitiating effi ciency and absorption characteristics at near UV range [ 57 ] but also their widespread applications such as printing inks, coatings, microelectronics, and photoresists, for particular applications in UV curing of heavily pigmented resins where the pigment (TiO 2 ) screens out much of the UV light from the irradiation source. Jiang [58][59][60] developed a series of amphipathic polymeric TX photoinitiators such as TX-GA (Figure 1 ), with a good solubility in both oil and aqueous medium.…”

“…Among them, TX-MPEG550 has been illustrated as the best hydrophilic visible photoinitiator in the presence of hydrogen donors and would have great potential applications in waterborne visible photocuring systems after carefully investigating the photopolymerization behavior of TX-MPEGs in different conditions. solubilizing groups onto a conventional photoinitiators, such as polysilane, [ 28,29 ] hydroxyalkylphenone, [ 30,31 ] Michler's ketone, [ 32 ] benzophenone, [ 33 ] anthraquinone, [ 34 ] xanthene, [ 35 ] α-diketones, [ 36,37 ] aliphatic ketones, [ 38 ] ribofl avin, [ 39 ] 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, [ 40 ] and TX [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] is a trend to obtain water-soluble photoinitiators.…”

Bisphosphonic Acid‐Functionalized Water‐Soluble Photoinitiators

“…This idea was applied to some other materials as well. For example, the ionic hydrophilic groups such as quaternary ammonium salts, carboxylic acids, sulfonates, thiosulfates, or neutral hydrophilic groups such as long ethoxy ether chains (PEGs), oligomeric structures such as polyvinyl alcohols were incorporated into conventional photoinitiators such as benzyl, anthraquinone, polysilanes, Michler's ketone, aliphatic ketones, benzophenone and thioxanthone . Other water‐soluble photoinitiators reported previously in the literature include benzylidine cyclano dyes, xanthene dyes, carboxylated camphorquinone, coumarin derivatives, naphthalimide derivatives, and hydoxyalkylphenones …”