LED‐Induced Polymerization (385, 405, and 455 nm) Using Star‐Shaped Tris(4‐(thiophen‐2‐yl)phenyl)amine Derivatives as Light‐Harvesting Photoinitiators. Issue 2 (29th October 2014)

• Record Type: Journal Article
• Authors: Zhang, Jing; Sallenave, Xavier; Bui, Thanh‐Tuan; Dumur, Frédéric; Xiao, Pu; Graff, Bernadette; Gigmes, Didier; Fouassier, Jean Pierre; Lalevée, Jacques
• Is Part Of: Macromolecular chemistry and physics. Volume 216:Issue 2(2015:Jan.)
• Page Start: 218
• Page End: 227
• Publication Date: 2014-10-29
• Subjects: Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.201400403
• Languages: English
• ISSNs: 1022-1352

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Two star‐shaped tris(4‐(thiophen‐2‐yl)phenyl)amine derivatives, namely tris(4‐(5‐(3‐pentylthieno[3, 2‐<italic>b</italic>]thiophen‐5‐yl)thiophen‐2‐yl)phenyl)amine and tris(4‐(5‐(3‐pentyl‐2‐(thiophen‐2‐yl)thieno[3, 2‐<italic>b</italic>]thiophen‐5‐yl)thiophen‐2‐yl)phenyl)amine, are developed as photoinitiators for radical and cationic polymerizations under near‐UV and visible light‐emitting diodes (LEDs) (e.g., 385, 405, and 455 nm). When used in combination with an iodonium salt (and optionally <italic>N</italic>‐vinyl carbazole) or an amine/alkyl halide couples, they lead to excellent photoinitiating abilities for the polymerization of epoxides or (meth)acrylates under air. Compared with commercial photoinitiators, i.e., camphorquinone‐based systems or bis(2, 4, 6‐trimethylbenzoyl)‐phenylphosphineoxide, the novel photoinitiators exhibit noticeably higher polymerization efficiencies under air (epoxide conversions = 41–57% vs ≈0%, halogen lamp exposure; methacrylate conversions = 50–55% vs 44%, LED at 405 nm exposure; methacrylate conversions = 34–42% vs 0–8%, LED at 455 nm exposure). These systems are also interesting in overcoming oxygen inhibition. The photochemical mechanisms are studied by steady‐state photolysis, electron spin resonance spin trapping, fluorescence, cyclic voltammetry, and laser flash photolysis techniques. <boxed-text content-type="graphic" position="anchor" orientation="portrait"><graphic position="anchor" mimetype="image" xlink:href="ark:/27927/pgh372tvw49" orientation="portrait" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /></boxed-text></p> </abstract>