Zinc complex based photoinitiating systems for acrylate polymerization under air; in situ formation of Zn-based fillers and composites

• Published in: Polymer chemistry 2014-11, Vol.5 (22), p.6569-6576
• Main Authors: Versace, D.-L, Bourgon, J, Leroy, E, Dumur, F, Gigmes, D, Fouassier, J. P, Lalevée, J
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Material chemistry
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/c4py00716f

[ N , N ′-Bis(salicylidene)-1,2-phenylenediamine]zinc( ii ) (ZnC) exhibits unexpected properties as a photoinitiator or additive for both free-radical photopolymerization reactions and in situ formation of Zn-based fillers under light activation and aerated conditions. The ZnC/2,2-dimethoxy-2-phenylacetophenone (DMPA) and ZnC/ N -methyldiethanolamine (MDEA) couples are characterized by remarkable properties: (i) a photoinitiating efficiency for the radical polymerization of an acrylate matrix under air higher than that of a reference Type I photoinitiator such as DMPA (final conversion of ∼30-45% vs. 15%) and therefore a good ability to overcome the oxygen inhibition effect and (ii) a never reported in situ formation of Zn-based fillers (100 μm thick sticks) or composites. The photochemical properties of the ZnC are investigated by fluorescence and UV-visible spectroscopy and Electron Spin Resonance (ESR). The photodecomposition of ZnC under air is governed by either an addition of peroxyl radicals onto ZnC when associated with DMPA, or a H-abstraction mechanism when combined with MDEA. When using a ZnC/MDEA/silver salt photoinitiating system, a highly efficient polymerization of the acrylate matrix under air and a concomitant in situ production of Ag(0) NPs are observed. Photoinitiating systems based on a zinc complex are used for avoiding the oxygen inhibition during the photopolymerization of acrylate and the generation of Zn fillers and Ag NPs.