title: One-component thioxanthone acetic acid derivative photoinitiator for free radical polymerization.
abstract: Acetic acid-based thioxanthone (TXCH2 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 TXCH2 COOH is similar to the parent thioxanthone and the triplet lifetime was calculated as 2.3 μs at 630 nm.
authors.affiliation: Department of Chemistry, Davutpasa Campus, Yildiz Technical University, Esenler, Istanbul, Turkey.
authors.forename: Duygu S
authors.initials: DS
authors.lastname: Esen
authors.forename: Gokhan
authors.initials: G
authors.lastname: Temel
authors.forename: Demet K
authors.initials: DK
authors.lastname: Balta
authors.forename: Xavier
authors.initials: X
authors.lastname: Allonas
authors.forename: Nergis
authors.initials: N
authors.lastname: Arsu
mesh_terms: D019342:Acetic Acid / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D058105:Polymerization; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013892:Thioxanthenes / Q000737:chemistry; D044004:Xanthones / Q000737:chemistry*
chemical_list: D005609:Free Radicals; D013892:Thioxanthenes; D044004:Xanthones; C484911:thioxanthone; D019342:Acetic Acid