Iodonium‐polyoxometalate and thianthrenium‐polyoxometalate as new one‐component UV photoinitiators for radical and cationic polymerization |
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Authors: | Haifaa Mokbel Pu Xiao Corine Simonnet‐Jégat Frederic Dumur Didier Gigmes Joumana Toufaily Tayssir Hamieh Jean Pierre Fouassier Jacques Lalevée |
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Institution: | 1. Institut de Science des Matériaux de Mulhouse IS2M, Mulhouse Cedex, France;2. Laboratoire de Matériaux, Catalyse, Environnement et Méthodes Analytiques (MCEMA‐CHAMSI), EDST, Université Libanaise, Beyrouth, Liban;3. Institut Lavoisier de Versailles, UMR CNRS 8180, Université de Versailles‐St‐Quentin, Versailles, France;4. Aix‐Marseille Université, CNRS, Institut de Chimie Radicalaire, Marseille, France;5. ENSCMu‐UHA, 3 rue Alfred Werner, Mulhouse Cedex, France |
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Abstract: | Four novel onium salts (onium‐polyoxometalate) have been synthesized and characterized. They contain a diphenyliodonium or a thianthrenium (TH) moiety and a polyoxomolybdate or a polyoxotungstate as new counter anions. Outstandingly, these counter anions are photochemically active and can sensitize the decomposition of the iodonium or TH moiety through an intramolecular electron transfer. The phenyl radicals generated upon UV light irradiation (Xe–Hg lamp) are very efficient to initiate the radical polymerization of acrylates. Cations are also generated for the cationic polymerization of epoxides. Remarkably, these novel iodonium and TH salts are characterized by a higher reactivity compared with that of the diphenyliodonium hexafluorophosphate and the commercial TH salt, respectively. Interpenetrating polymer networks can also be obtained under air through a concomitant cationic/radical photopolymerization of an epoxy/acrylate blend (monomer conversions > 65%). The photochemical mechanisms are studied by steady‐state photolysis, cyclic voltammetry, and electron spin resonance techniques. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 981–989 |
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Keywords: | cationic photopolymerization interpenetrating polymer networks iodonium salts photochemistry photoinitiators photopolymerization polyoxometalates radical photopolymerization thianthrenium salts |
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