Details

Autor(en) / Beteiligte

• Kocaarslan, Azra
• Tabanli, Sevcan
• Eryurek, Gonul
• Yagci, Yusuf

Titel

Near‐Infrared Free‐Radical and Free‐Radical‐Promoted Cationic Photopolymerizations by In‐Source Lighting Using Upconverting Glass

Ist Teil von

• Angewandte Chemie International Edition, 2017-11, Vol.56 (46), p.14507-14510

Auflage

International ed. in English

Ort / Verlag

Germany: Wiley Subscription Services, Inc

Erscheinungsjahr

2017

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A method is presented for the initiation of free‐radical and free‐radical‐promoted cationic photopolymerizations by in‐source lighting in the near‐infrared (NIR) region using upconverting glass (UCG). This approach utilizes laser irradiation of UCG at 975 nm in the presence of fluorescein (FL) and pentamethyldiethylene triamine (PMDETA). FL excited by light emitted from the UCG undergoes electron‐transfer reactions with PMDETA to form free radicals capable of initiating polymerization of methyl methacrylate. To execute the corresponding free‐radical‐promoted cationic polymerization of cyclohexene oxide, isobutyl vinyl ether, and N‐vinyl carbazole, it was necessary to use FL, dimethyl aniline (DMA), and diphenyliodonium hexafluorophosphate as sensitizer, coinitiator, and oxidant, respectively. Iodonium ions promptly oxidize DMA radicals formed to the corresponding cations. Thus, cationic polymerization with efficiency comparable to the conventional irradiation source was achieved. Free‐radical and free‐radical‐promoted cationic polymerization is stimulated by in‐source lighting in the near‐infrared region. Yb3+/Tm3+ codoped tungsten–tellurite upconverting glass (UCG) irradiated by a laser, in the presence of fluorescein (FL) dye/amine and iodonium salt combinations, generates free radicals capable of initiating polymerization. Key: dimethyl aniline (DMA), pentamethyldiethylene triamine (PMDETA).