A study of the elemental reactions involved in the initiation of the polymerization of tetrahydrofuran induced by the photosensitization of a triphenylsulphonium salt by perylene

Abstract

A fotopolimerização de THF foi estudada na presença de sal de trifenilsulfônio e perileno. O mecanismo envolve uma transferência de elétron do estado singlete excitado do perileno para os íons trifenilsulfônio, levando à formação de cátions radicais, que reagem com o tetrahidrofurano. O rendimento aparente de cátions radicais calculado do mecanismo proposto tem o mesmo comportamento geral que as velocidades de polimerização medidas experimentalmente.

The synthesis of novel, visible-wavelength, oxidizable polymerization sensitizers based on the 8-halogeno-5,12-dihydroquinoxalino[2,3-b]quinoxaline skeleton

“…Free radical photopolymerization reactions were conducted in solvent mixture of 1 ml of 1-methyl-2-pyrrolidone (MP) and 4 ml of trimethylolpropane triacrylate. The concentrations of dye and N-alkoxypyridinium salts (5,6) were maintained at 0.1 mM and 10 mM, respectively. The solutions were degassed prior to the experiments by bubbling with N 2 for 10 min and they were irradiated for 120 s. The rate of polymerization (R p ) and the double bond conversion (p) were calculated from Eqs.…”

“…In order to extend the spectral sensitivity of these initiators to the visible light, sensitizers are used. The most efficient and generally applicable mechanisms of photosensitization of diaryliodonium [4], triphenylsulfonium [5], and N-alkoxypyridinium [6] salts are photoinduced intermolecular electron transfer processes. In such processes, the photo-excited sensitizer (Dye*) is oxidized by the salt (X-Y þ ) to form a corresponding radical cation (Dye þ ) and iodonium/pyridinium salt radical (X-Y ) that undergoes cleavage as depicted in Scheme 3.…”

“…Photosensitizers for acrylate monomers include cyanine [7], coumarin [7], and acridinedione dyes [8]. Cationic polymerization reactions can be initiated by perylene [6], coumarin [9], and curcumin [10] dyes. In cationic initiation, the excited states of the dyes transfer electrons to the onium salts.…”

Fotopolimerização: princípios e métodos

“…Neste sentido têm sido utilizadas técnicas como, por exemplo, dilatometria [30,[32][33][34][35] , espectroscopia fotoacústica [36] , espectroscopia de infravermelho (IR) [37,38] , calorimetria diferencial [39][40][41] , espectroscopia Raman [42,43] , espalhamento de luz [44] , e ressonância paramagnética eletrônica [45,46] .…”

Dynamical Model to Describe the Interactions between the Chemical Components in Environment of Photopolymerization of MMA by Dye/Amine Systems

“…The applications commonly appear in industry of biomaterials and manufactured products [3,4]. On the other hand, basic studies such as polymer formation, theoretical and experimental, or studies around the physical chemistry properties of polymers can be cited [5][6][7][8][9][10][11][12][13][14][15][16].…”