title: Photochemistry of tetraphenyldiboroxane and its use as photopolymerization coinitiator.
abstract: 2-Hydroxyethyl methacrylate (HEMA) was photopolymerized in the presence of Safranine (SfH(+)) and tetraphenyldiboroxane (TPhB). Polymerization results are correlated with the photochemistry of TPhB and its ability to aggregate forming hydrophobic domains (critical aggregation concentration, cac, 1.2 × 10(-4) M). Polymerization was not observed when the TPhB concentration was below the cac, indicating that the polymerization is initiated in the hydrophobic environment. The quenching of the triplet state of SfH(+) by TPhB and the generation of the semireduced species of SfH(+) suggests an electron transfer from the boron compound to the excited dye, and that the resulting boron-centered radical initiates the polymerization process.
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.
authors.forename: Willy G
authors.initials: WG
authors.lastname: Santos
authors.forename: Carla C
authors.initials: CC
authors.lastname: Schmitt
authors.forename: Miguel G
authors.initials: MG
authors.lastname: Neumann
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D010777:Photochemistry; D058105:Polymerization; D013050:Spectrometry, Fluorescence
chemical_list: D001896:Boron Compounds