Cationic photopolymerization of carbazolyl-containing vinyl ethers

Budreckienė, Rūta; Lazauskaité, Rüta; Buika, Gintaras; Gražulevičius, Juozas V.

doi:10.1016/s1010-6030(03)00076-5

Cited by 11 publications

(7 citation statements)

References 11 publications

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“…Ar ● and DM2 ●+ can be considered as the initiating species for the radical polymerization and the CP, respectively (Scheme ). Alternatively, in presence of radical cations, the release of initiating Bronsted acid for CP can also be observed.…”

Section: Resultsmentioning

confidence: 99%

Development of new high‐performance visible light photoinitiators based on carbazole scaffold and their applications in 3d printing and photocomposite synthesis

Abdallah

Magaldi

Hijazi

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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In this article, new compounds based on the carbazole scaffold (DMs = DM1 and DM2, constituted by a carbazole unit connected on positions 3 and 6 to a two 4,4 0dimethoxydiphenylamine groups and differing by the substituent present on the nitrogen heteroatom of the carbazole core) were synthesized and proposed as high-performance visible light photoinitiators/photosensitizers for both the free-radical polymerization of methacrylates and the cationic polymerization of epoxides upon visible light exposure using LED@405 nm. Remarkably, DM2 leads to higher final conversions than DM1. In order to study the photophysical and photochemical properties of the carbazole derivatives, different parameters were taken into account such as the light absorption, the steady-state photolysis, and the fluorescence spectroscopy. Using different techniques such as fluorescence quenching, redox behavior, and cyclic voltammetry, we are able to discuss the photosensitization/photoinitiation reactions providing a full coherent picture of the involved chemical mechanisms. The photosensitization of the carbazole derivatives occurred predominantly via singlet excited states at the rate of the diffusion limit. Upon exposure to laser diode at 405 nm, DMs show high performance in initiating systems for 3D resins. Remarkably, DM2 can also be used in photocomposite synthesis using light-emitting diode conveyor. 1 H NMR 250 MHz (DMSO-d 6 ) δ 3.72 (s, 12H), 5.25 (d, 1H, J trans = 12.6 Hz), 5.08 (d, 1H, J cis = 20.4 Hz), 6.71 (dd, 1H, J cis = 22.0 Hz, J trans = 13.5 Hz), 6.82-6.91 (m, 16H), 7.12 (dd, 2H, J o = 10.3 Hz, J m = 2.9 Hz), 7.25 (d, 2H, J o = 9.6 Hz), 7.44 (d, 2H, J o = 9.9 Hz), 7.58 (d, 2H, J o = 10.5 Hz), 7.73 (d, 2H, J m = 2.1 Hz).

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Section: Resultsmentioning

confidence: 99%

Development of new high‐performance visible light photoinitiators based on carbazole scaffold and their applications in 3d printing and photocomposite synthesis

Abdallah

Magaldi

Hijazi

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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“…The efficiency trend for (coumarin/IOD) couples for CP (i.e., for the Rp) respects the following order: coumarin 3 > coumarin 1 > coumarin 2 > coumarin 7 > coumarin 4 > coumarin 8 > coumarin 5 > coumarin 6 which is directly linked to the light absorption properties of the examined coumarins ( ε @405 nm ), their photochemical reactivity ( Δ G et(Coumarin/IOD) ; see in Table 3 ), and also to the reactivity of the generated radical cations (Coumarin ●+ ) which can have a huge effect on the photoinitiating ability. Furthermore, the reactivity of the system may also be affected by the formation of Brønsted acid which can be considered as the initiating species for the CP, as reported in [ 29 ]. Finally, the free energy changes (ΔG et ) for the electron transfer reaction which occurs between coumarins as electron donors and IOD as electron acceptor (via singlet or triplet excited states) were calculated according to the equation 1 using the oxidation potentials E ox (determined by cyclic voltammetry) and the excited state energies (E S1 : the crossing point between the absorption and the fluorescence spectra or E T1 : calculated triplet state energy level at DFT level) of the coumarins ( Table 3 ).…”

Section: Resultsmentioning

confidence: 99%

Coumarins as Powerful Photosensitizers for the Cationic Polymerization of Epoxy-Silicones under Near-UV and Visible Light and Applications for 3D Printing Technology

et al. 2020

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In this study, eight coumarins (coumarins 1–8) are proposed as near-UV and blue light sensitive photoinitiators/photosensitizers for the cationic polymerization (CP) of epoxysilicones when combined with 4-isopropyl-4’-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate (IOD). Among these coumarins, four of them (coumarins 1, 2, 6 and 8) have never been reported in the literature, i.e., these structures have been specifically designed to act as photoinitiators for silicones upon near UV and visible irradiation. Good final reactive epoxy function conversions (FCs) and also high rates of polymerization (Rp) were achieved in the presence of the newly proposed coumarin-based systems. The polymers generated from the photopolymerization of epoxysilicones can be considered as attractive candidates for several applications such as: elastomers, coatings, adhesives, and so on. The goal of this study focuses also on the comparison of the new proposed coumarins with well-established photosensitizers i.e., 1-chloro-4-propoxythioxanthone (CPTX), 9,10-dibutoxyanthracene (DBA) or some commercial coumarins (Com. Coum). As example of their high performance, the new proposed coumarins were also used for laser write experiments upon irradiation with a laser diode at 405 nm in order to develop new cationic 3D printing systems.

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“…Otherwise, the reactivity of the generated radical cations (Dye •+ ) can significantly affect the initiating abilities of the involved systems (see the chemical mechanisms below). In addition, the formation of Brønsted acid as initiating species [39] can also influence the reactivity of the system.…”

Section: Cationic Polymerization (Cp) Of Epoxides (Epox)mentioning

confidence: 99%

High performance dyes based on triphenylamine, cinnamaldehyde and indane-1,3-dione derivatives for blue light induced polymerization for 3D printing and photocomposites

et al. 2020

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In this research, high performance dyes based on triphenylamine, cinnamaldehyde and indane-1,3-dione derivatives have been designed/synthesized and evaluated as photoinitiators for visible light photopolymerization. The introduction of light-emitting diodes (LEDs) as low-cost and secured sources of irradiation is one of the major purposes in this study, where a LED at 405 nm was used for both the cationic polymerization (CP) of thin epoxide samples and the free radical polymerization (FRP) of thin TMPTA films. The proposed dyes showed very high efficiencies in the presence of the two-component photoinitiating systems based on Dye/Iodonium salt (Iod) couples or Dye/Amine (such as N-Phenylglycine (NPG) or ethyl 4-(dimethylamino)benzoate (EDB)) couples for the FRP and/or CP, highlighting their importance through a photo-oxidation (with Iod) process but also through a photo-reduction (with amine) process. The examined dyes are also able to initiate the FRP of thin acrylate films in the presence of the three-component (Dye/Iod/NPG) systems where very high rates of polymerization (Rp) and great final reactive function conversions (FCs) were achieved. Objectives of this work concern the study of the photoinitiating abilities of the different photoinitiating systems using FTIR technique but also the

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Cationic photopolymerization of carbazolyl-containing vinyl ethers

Cited by 11 publications

References 11 publications

Development of new high‐performance visible light photoinitiators based on carbazole scaffold and their applications in 3d printing and photocomposite synthesis

Development of new high‐performance visible light photoinitiators based on carbazole scaffold and their applications in 3d printing and photocomposite synthesis

Coumarins as Powerful Photosensitizers for the Cationic Polymerization of Epoxy-Silicones under Near-UV and Visible Light and Applications for 3D Printing Technology

High performance dyes based on triphenylamine, cinnamaldehyde and indane-1,3-dione derivatives for blue light induced polymerization for 3D printing and photocomposites

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