Highly conjugated visible and near-infrared light photoinitiating systems for radical and cationic polymerizations

Suerkan, Ali; Alkan, Ecem Aydan; Kaya, Kerem; Udum, Yasemin Arslan; Toppare, Levent; Yaǧcı, Yusuf

doi:10.1016/j.porgcoat.2021.106189

Cited by 11 publications

(7 citation statements)

References 39 publications

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“…Both free‐radical, [32,33] cationic [34,35] and step‐growth [36] polymerizations have been adapted to photochemical processes to benefit from these advantages [37,38] . In this context, many cationic photoinitiators are known and their photochemistry has been intensively studied [39–42] . Among them, onium‐type photoinitiators have attracted growing interest over conventional metallo‐organic complexes, due to their numerous advantages such as thermal stability, solubility, efficiency in generating reactive species upon photolysis and leaving no trace of metal residues [43,44] .…”

Section: Introductionmentioning

confidence: 99%

Directly and Indirectly Acting Photoinitiating Systems for Ring‐Opening Polymerization of ϵ‐Caprolactone

2021

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Directly and indirectly acting photoinitiating systems for cationic ring opening polymerization (ROP) of ϵ‐caprolactone (ϵ‐CL) by using diphenyl iodonium salt (DPI) in the presence of benzyl alcohol were studied and mechanistic details were evaluated. In the direct system, the polymerization is initiated by a Brønsted acid formed upon UV irradiation of DPI. Polymerizations by indirectly acting photoinitiating systems proceeding via electron transfer reactions of photochemically formed electron donor radicals or excited states of polynuclear aromatic compounds with DPI were investigated. It was demonstrated that polymerizations proceed in a controlled manner by an activated monomer (AM) mechanism. Applicability of the photoinitiation to the other lactone monomers was validated on the example of δ‐ valerolactone (δ‐VL).

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Section: Introductionmentioning

confidence: 99%

Directly and Indirectly Acting Photoinitiating Systems for Ring‐Opening Polymerization of ϵ‐Caprolactone

2021

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“…[17] All modes of chain polymerizations, namely radical, cationic and anionic polymerizations can be conducted by photochemical means with spectral selectivity in full electro-magnetic spectrum, including visible and Nearinfrared region. [18] Recent progress on photoinduced controlled/living polymerizations and ligation processes provided possibility to form complex macromolecules with welldefined structures and functionalities. [19] However, in comparison to the extensive application of photochemical methods in these systems, the corresponding step-growth polymerization are scarcely investigated due to the low photosensitivity of the related monomers to generate reactive species.…”

Section: Introductionmentioning

confidence: 99%

Phenacyl Bromide as a Single‐Component Photoinitiator: Photoinduced Step‐Growth Polymerization ofN‐Methylpyrrole andN‐Methylindole

et al. 2022

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The synthesis of step-growth polymers by photoinduced methods is a challenging issue in synthetic chemistry. Here, we report a single component near UV responsive photopolymerization system for step-growth polymerization of N-methylpyrrole (MPyr) and N-methylindole (MIn) by using phenacyl bromide (PAB). The obtained high molecular weight conjugated polymers were characterized by spectral and chromatographic methods. Detailed laser flash photolysis and spectroscopic studies revealed that polymerization proceeds by successive photoinduced cleavage of PAB followed by electron transfer, proton release and coupling processes. After photolysis, chain growth continues also in daylight or dark by acidic oxidation. The structural features of the polymers were investigated. PAB single component photoinitiator enables an efficient, rapid, room temperature step-growth polymerization process of MPyr and MIn that can be applied to other conjugated monomers.

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“…A CTC is an electron donor–acceptor complex that consists of two or more molecules with different electron‐withdrawing or electron‐releasing abilities. When visible light is absorbed, these molecular complexes can enter an excited electronic state followed by charge transfer from the HOMO level of the donor molecule to the LUMO level of the acceptor 32 . More recently, the use of upconverting nanoparticles, 33 graphene oxide 34 and fullerene 35 and chemiluminescence 36 have been introduced as alternative wavelength‐shifting approaches for the initiation of cationic polymerization.…”

Section: Introductionmentioning

confidence: 99%

Highly conjugated isoindigo and quinoxaline dyes as sunlight photosensitizers for onium salt‐photoinitiated cationic polymerization of epoxy resins

Ercan

Gultekin

Yeşil

et al. 2022

Polymer International

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In this study, photoinitiated cationic polymerization of epoxy resins by photoinduced electron transfer reactions using four new chromophoric dyes, namely (3E)‐1,1′‐bis(2‐ethylhexyl)‐6,6′‐dipyren‐1‐yl‐3,3′‐biindole‐2,2′(1H,1′H)‐dione (ISOIV), (3′E)‐1,1′′′‐diethyl‐1′,1′′‐bis(2‐ethylhexyl)‐1H,1′′′H‐5,6′:3′,3′′:6′′,5′′′‐quaterindole‐2′,2′′(1′H,1′′H)‐dione (ISOV), (3E)‐6,6′‐bis(9‐ethyl‐9H‐carbazole‐3‐yl)‐1‐[(2R)‐2‐ethylhexyl]‐1′‐[(2S)‐2‐ethylhexyl]‐3,3′‐biindole‐2,2′(1H,1′H)‐dione (ISOVIII) and 3,3′‐(6‐bromokinoksalin‐2,3‐diyl)bis(9‐ethyl‐9H‐carbazole) (TPDC6), and diphenyliodonium hexafluorophosphate (Ph2I+PF6−; DPI) under sunlight is reported. Upon irradiation, photoexcited dye forms an exciplex with DPI. Electron transfer reactions within the exciplex result in the formation of ionic species capable of initiating ring‐opening polymerization of an epoxy resin. It is shown that among the investigated dyes, ISOVIII and TPDC6 exhibited higher initiation efficiency in accordance with their stronger electron‐donating nature due to the presence of carbazole groups. © 2021 Society of Industrial Chemistry.

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Highly conjugated visible and near-infrared light photoinitiating systems for radical and cationic polymerizations

Cited by 11 publications

References 39 publications

Directly and Indirectly Acting Photoinitiating Systems for Ring‐Opening Polymerization of ϵ‐Caprolactone

Directly and Indirectly Acting Photoinitiating Systems for Ring‐Opening Polymerization of ϵ‐Caprolactone

Phenacyl Bromide as a Single‐Component Photoinitiator: Photoinduced Step‐Growth Polymerization ofN‐Methylpyrrole andN‐Methylindole

Highly conjugated isoindigo and quinoxaline dyes as sunlight photosensitizers for onium salt‐photoinitiated cationic polymerization of epoxy resins

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