Naphthalimide based methacrylated photoinitiators in radical and cationic photopolymerization under visible light

Abstract

International audienceThe abilities of two naphthalimide derivatives with a methacryloyl group to initiate, when incorporated in multi-component systems, a ring-opening polymerization of epoxides and a radical polymerization of acrylates under different irradiation sources (e.g. very soft halogen lamp irradiation, laser diode at 457 nm, laser diode at 405 nm and blue LED bulb at 462 nm) have been investigated. One of them is particularly efficient for the cationic and radical photopolymerization of an epoxide/acrylate blend in a one-step hybrid cure and leads to the formation of an interpenetrated polymer network IPN (30 s for getting tack free coatings). The migration stability of one of these naphthalimide derivatives is found to be excellent in the cured polyacrylates and IPNs. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, electron spin resonance spin trapping and laser flash photolysis techniques

Photochemical Production of Interpenetrating Polymer Networks; Simultaneous Initiation of Radical and Cationic Polymerization Reactions

“…The final coatings are tack-free. Such useful PIs in these novel dual photoinitiating systems are derived from dye structures and include e.g., diketopyrrolopyrrole-thiophene derivatives [107], mono and polyfunctional thiophene derivatives [108], indanedione skeleton [109], naphthalene scaffold [110], naphthalimide and naphthalic anhydride derivatives [111], anthraquinone derivatives [112], chalcone derivatives [113], push-pull malonate and malonitrile based compounds [114], naphthalimide based methacrylated derivatives [115], α-silicon polyoxomolybdate [116], acridinediones [117], difunctional acridinediones [118], Keggin-type polyoxometalate ion [119], push-pull structured indandiones [120], dimethyldihydropyrene [121], chromone based compounds [122], perylene bis-dicarboximides [123], pyrene derivatives [124], zinc complexes [125], pyridinium salts [126], pyrromethenes [127], trifunctional triazines [128], cyclometallated Pt(II) complexes [129], polyaromatic structures [130], and phenanthroline ligand containing Ru complex [131].…”

“…The high reactivity of the photoinitiating systems is exemplified by the fact that low viscosity formulations where oxygen inhibition is much more important can be used (e.g., acrylate (TMPTA)/epoxide (EPOX), acrylate (TMPTA)/divinylether (DVE), thiol (trimethylolpropane tris (3-mercaptopropionate) TMSH)/divinylether (DVE)). For example, the manufacture of IPN materials can be carried out under exposure to a large variety of wavelengths delivered by a Hg-Xe lamp (intensity ~40 mW/cm −2 ) [116,119,128,130] or laser diodes (intensity ~80 mW/cm −2 ) at 385-405 nm [110], 457 nm [108,111,[113][114][115]122,124], 473 nm [127], 473 nm (and likely 532, 635 nm) [120], 532 nm [107,123], 635 nm [112], from 473 up to 635 nm [121]. This was achieved under air (for EPOX/TMPTA blends) or in laminate (for EPOX/DVE blends as seen, e.g., in [124,125,127,128]).…”

Difunctional monomeric and polymeric photoinitiators: Synthesis and photoinitiating behaviors

“…2). 13 C NMR spectra of all monomers show the disappearance of the methylene carbon of CMAC at 41.5 ppm (CH 2 C1) and the appearance of a new oxymethylene carbon around 66 ppm. The two peaks seen around 163.0 and 196.0 ppm are typical for the C O of ester and ketone groups.…”

“…The development of novel photoinitiators endowed with better properties such as high photoreactivity, good solubility in the formulation, low odor and toxicity, no darkening due to the migration of residues in the cured film and good storage stability has become an important issue [4]. Therefore in recent years, polymerizable [5][6][7][8][9][10][11][12][13][14][15], oligomeric or polymeric photoinitiators (PPIs) [16][17][18][19][20][21][22][23] meeting most of the above mentioned requirements received continued interest due to their advantages in comparison with their corresponding low molecular weight non-monomeric analogs. The photoinitators derived from dendrimers and hyperbranched polymers were reported for their high functionality and low viscosity compared to linear polymers [24][25][26][27][28][29].…”

Structure-reactivity relationships of novel monomeric photoinitiators

“…Small molecular weight commercial photoinitiators do not exhibit all of these properties. Therefore, in recent years, the development of monomeric (MPI) [5][6][7][8][9][10][11][12] and polymeric photoinitiators (PPIs) [13][14][15][16][17][18][19][20][21][22][23][24][25] which do, has become an important issue.…”