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Electron Transfer Photoinitiating Systems. The Effect of the Co‐Initiator Structure on the Photoinitiation Ability of a Photoredox Pair Containing Neutral Hemicyanine Dyes as Sensitizers
Author(s) -
Kabatc Janina,
Jędrzejewska Beata,
Pączkowski Jerzy
Publication year - 2006
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.200600059
Subject(s) - photochemistry , electron transfer , electron acceptor , photoinduced electron transfer , chemistry , electron donor , polymerization , photopolymer , singlet state , benzoxazole , radical polymerization , reactivity (psychology) , excited state , materials science , polymer , organic chemistry , physics , nuclear physics , catalysis , medicine , alternative medicine , pathology
Summary: The photoinitiation ability of photoredox pairs composed of a neutral hemicyanine dye and different co‐initiators for the free radical polymerization of 2‐ethyl‐2‐(hydroxymethyl)propane‐1,3‐diol triacrylate is investigated. p ‐( N , N ‐dimethylaminostyryl)benzthiazole, p ‐( N , N ‐dimethylaminostyryl)benzoxazole, p ‐( N , N ‐dimethylaminostyryl) α ‐naphthiazole are tested as dyes, and, as co‐initiators, an aromatic amino‐acid, an aromatic thio‐ and oxycarboxylic acid, and alkyltriphenylborate are applied as electron donors. N , N′ ‐dialkoxybipyridinium salts are used as ground‐state electron acceptors. The experimental results show that the photoinitiating ability of the tested photoredox pairs are controlled by both the driving force of the electron transfer process between an electron donor and an electron acceptor and the reactivity of the free radical that results from the secondary reactions occurring after the photoinduced electron transfer process. The greatest photoinitiation ability of free radical polymerization is observed when the tested dyes are applied as electron donors in their singlet excited states in combination with N , N′ ‐dialkoxybipyridinium salts acting as ground‐state electron acceptors.Schematic of the investigated photoinitiation systems.