scholarly journals Ketone Number and Substitution Effect of Benzophenone Derivatives on the Free Radical Photopolymerization of Visible-Light Type-II Photoinitiators

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1801
Author(s):  
Tung-Liang Huang ◽  
Yung-Chung Chen
Keyword(s):  
Free Radical ◽  
Visible Light ◽  
Substitution Effect ◽  
Cyclic Voltammograms ◽  
Reaction Behavior ◽  
Free Radical Photopolymerization ◽  
Spin Resonance ◽  
Double Bond Conversion ◽  
Uv Lamp ◽  
Electron Donating Groups

Three novel visible-light absorbing benzophenone-based hydrogen acceptors (BPD-D, BPDM-D and BPDP-D) were designed on the basis of a donor–benzophenone–donor structural backbone. Mono or diketone units and double diphenylamine electron-donating groups in para-or meta-positions were introduced to comprehend the electronic and structural effects on free radical photopolymerization (FRPP). Such a structural change leads not only to a red-shift of the absorption maxima but strongly enhances their molar extinction coefficients compared to the commercial phototinitiators such as benzophenone (BP) and 4,4′-bis(diethylamino) benzophenone (EMK). In addition, excellent melting points and thermal decomposition temperatures were achieved for those novel compounds. Further, the photochemical reaction behavior was studied by cyclic voltammograms (CV), photolysis and electron spin resonance (ESR) spectroscopy. Finally, benzophenone derivatives in combination with an amine (TEA, triethylamine) as a co-initiator were prepared and initiated the FRPP of trimethylolpropane trimethacrylate (TMPTMA) using a UV lamp as a light source. When used in stoichiometric amounts, the BPDP-D/TEA had the best double bond conversion efficiency among all the compounds studied, and were even superior to the reference compounds of BP/TEA and EMK/TEA. The results and conclusions could provide the fundamental rules applicable for the structural design of benzophenone derivative-based photoinitiators.

Substituent Effects on Photoinitiation Ability of Coumarin-Based Oxime-Ester Photoinitiators for Free Radical Photopolymerization

2021 ◽  
Author(s):  
Jacques Lalevée ◽  
Fatima Hammoud ◽  
Nicolas giacoletto ◽  
Guillaume Noirbent ◽  
Bernadette Graff ◽  
...  
Keyword(s):  
Free Radical ◽  
Visible Light ◽  
Substituent Effects ◽  
Free Radical Photopolymerization

In this paper, a series of coumarin chromophore-based oxime-esters was designed and synthesized as visible light photoinitiators (PIs). Interestingly, upon exposure to irradiation of a LED at 405 nm, the...

scholarly journals Free Radical Photopolymerization and 3D Printing Using Newly Developed Dyes: Indane-1,3-Dione and 1H-Cyclopentanaphthalene-1,3-Dione Derivatives as Photoinitiators in Three-Component Systems

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 463 ◽  
Author(s):  
Ke Sun ◽  
Corentin Pigot ◽  
Hong Chen ◽  
Malek Nechab ◽  
Didier Gigmes ◽  
...  
Keyword(s):  
Free Radical ◽  
3D Printing ◽  
High Performance ◽  
Chemical Mechanisms ◽  
Esr Spin Trapping ◽  
Free Radical Photopolymerization ◽  
Spin Resonance ◽  
Component Systems ◽  
Iodonium Salt ◽  
First Time

The design of photoinitiating systems with excellent photochemical reactivities at 405nm LED is one of the obstacles to efficiently promote free radical polymerization in mild conditions (e.g., low light intensity, under air). Here, our actual search for new multicomponent photoinitiating systems at 405nm LED prompts us to develop new dyes based on push–pull structures. In the present paper, we chose two series of new dyes which possess indane-1,3-dione and 1H-cyclopenta naphthalene-1,3-dione groups as the electron-withdrawing groups, since they have the great potential to behave as sensitive and remarkable photoinitiators in vat photopolymerization/3D printing. When incorporated with a tertiary amine (ethyl dimethylaminobenzoate EDB, used as electron/hydrogen donor) and an iodonium salt (used as electron acceptor) as the three-component photoinitiating systems (PISs), and among a series of 21 dyes, 10 of them could efficiently promote the free radical photopolymerization of acrylates. Interestingly, steady state photolysis experiments revealed different behaviors of the dyes. Fluorescence experiments and free energy change calculations for redox processes were also carried out to investigate the relevant chemical mechanisms. Additionally, the formation of radicals from the investigated PISs was clearly observed by electron spin resonance (ESR) spin-trapping experiments. Finally, stereoscopic 3D patterns were successfully fabricated by the laser writing technique. In this work, the use of push–pull dyes based on the naphthalene scaffold as photoinitiators of polymerization is reported for the first time in a systematic study aiming at investigating the structure–performance relationship for irradiation carried out at 405 nm. By carefully selecting the electron donors used in the two series of push–pull dyes, novel and high-performance photoinitiating systems operating at 405 nm are thus proposed.

Synthesis and free radical photopolymerization of triphenylamine-based oxime ester photoinitiators

2021 ◽  
Vol 12 (9) ◽  
pp. 1286-1297
Author(s):  
Zhong-Han Lee ◽  
Fatima Hammoud ◽  
Akram Hijazi ◽  
Bernadette Graff ◽  
Jacques Lalevée ◽  
...  
Keyword(s):  
Free Radical ◽  
Visible Light ◽  
Photochemical Reaction ◽  
Free Radical Photopolymerization

Four visible light triphenylamine-based oxime ester photoinitiators (TP-1–4) were synthesized successfully. Photochemical reaction, photoreactivity and 3D pattern experiments were also conducted.

Esr Indication of Heavy Metal Contamination of Urban Atmosphere

1993 ◽  
Vol 27 (7-8) ◽  
pp. 263-269 ◽  
Author(s):  
B. Iosefzon-Kuyavskaya ◽  
N. Myrlyan ◽  
A. Shames
Keyword(s):  
Heavy Metal ◽  
Air Pollution ◽  
Electron Spin Resonance ◽  
Free Radical ◽  
Metal Contamination ◽  
Heavy Metal Contamination ◽  
Urban Atmosphere ◽  
Stable Free Radical ◽  
Spin Resonance ◽  
Line Characteristic

Electron Spin Resonance (ESR) was used for the examination oi dust samples collected from snow in an urban area. On the main doublet ESR line attributed to the signal of paramagnetic metals, a singlet line characteristic for stable free radical centers (FRC) was observed. A negative correlation of significant level between FRC signal intensity and heavy metal (HM) content was established. It was shown that FRC line intensity of dust may be used as a surrogate parameter for the estimation of air pollution by HM.

Design, Synthesis and Use of Phthalocyanines as a New Class of Visible-Light Photoinitiators for Free-Radical and Cationic Polymerizations

2021 ◽  
Author(s):  
Davy-Louis Versace ◽  
Louise Breloy ◽  
Yusuf Yagci ◽  
Ismail Yilmaz ◽  
Ozgur Yavuz
Keyword(s):  
Free Radical ◽  
Visible Light ◽  
Design Synthesis ◽  
New Class ◽  
Optical Stability ◽  
Cationic Polymerizations

Phthalocyanines (Pcs) are interesting molecules offering a fascinating chemistry world which received tremendous interest in the last decade. Their certain features such as high thermal, chemical, and optical stability as...

scholarly journals Cubane Cu4I4(phosphine)4 Complexes as New Co-initiator for Free Radical Photopolymerization: Towards Aromatic Amine-Free Systems

2021 ◽  
Author(s):  
Jacques Lalevée ◽  
Fatima Hammoud ◽  
Mahmoud Rahal ◽  
Julien Egly ◽  
Fabrice Morlet-Savary ◽  
...  
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Aromatic Amine ◽  
Free Radical Polymerization ◽  
Copper Iodide ◽  
Free Radical Photopolymerization ◽  
Acrylate Monomers ◽  
First Time

The investigation of copper-iodide cubane derivatives as new co-initiators for the free radical polymerization (FRP) of acrylate monomers under mild irradiation conditions is described for the first time here. These...

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