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One‐Component Thioxanthone Acetic Acid Derivative Photoinitiator for Free Radical Polymerization
Author(s) -
Esen Duygu S.,
Temel Gokhan,
Balta Demet K.,
Allonas Xavier,
Arsu Nergis
Publication year - 2013
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12218
Subject(s) - thioxanthone , photoinitiator , photochemistry , phosphorescence , chemistry , photopolymer , intersystem crossing , triplet state , flash photolysis , quantum yield , methyl methacrylate , ultrafast laser spectroscopy , benzil , polymerization , singlet state , fluorescence , excited state , organic chemistry , kinetics , laser , monomer , polymer , reaction rate constant , physics , catalysis , optics , quantum mechanics , molecule , nuclear physics
Acetic acid–based thioxanthone ( TXCH 2 COOH ) was synthesized and characterized and used as a photoinitiator for free radical photopolymerization of methyl methacrylate ( MMA ) in the absence and presence of a tertiary amine ( MDEA ) in different solvents. Different absorption properties were observed depending on the solvent. Fluorescence and phosphorescence experiments were also carried out successfully. The fluorescence quantum yield was found to be 0.09 and the phosphorescence lifetime was calculated as 138 ms at 77 K. The photoinitiator undergoes efficient intersystem crossing into the triplet state and the lowest triplet state possesses π – π * configuration. Laser flash photolysis experiments show that transient absorption of TXCH 2 COOH is similar to the parent thioxanthone and the triplet lifetime was calculated as 2.3 μs at 630 nm.