LED-induced polymerization (385, 405, and 455 nm) using star-shaped tris(4-(thiophen-2-yl)phenyl)amine derivatives as light-harvesting photoinitiators

Jing Zhang, Xavier Sallenave, Thanh Tuan Bui, Frédéric Dumur, Pu Xiao, Bernadette Graff, Didier Gigmes, Jean Pierre Fouassier, Jacques Lalevée

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23 Citations (Scopus)

Abstract

Two star-shaped tris(4-(thiophen-2-yl)phenyl)amine derivatives, namely tris(4-(5-(3 pentylthieno[3,2- b ]thiophen-5-yl)thiophen-2-yl)phenyl)amine and tris(4-(5-(3-pentyl-2 (thiophen-2-yl)thieno[3,2- b ]thiophen-5-yl)thiophen-2-yl)phenyl)amine, are developed as photoinitiators for radical and cationic polymerizations under near-UV and visible lightemitting diodes (LEDs) (e.g., 385, 405, and 455 nm). When used in combination with an iodonium salt (and optionally N -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.

Original languageEnglish
Pages (from-to)218-227
Number of pages10
JournalMacromolecular Chemistry and Physics
Volume216
Issue number2
DOIs
Publication statusPublished - Jan 2015
Externally publishedYes

Keywords

  • Cationic photopolymerization
  • Photoinitiators
  • Radical photopolymerization
  • Triphenylamine dyes
  • UV or visible LEDs

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