Polymerization of HEMA photoinitiated by the Safranine/diphenylborinate system

Autor(es)

Santos, Willy G. ^[1] ; Schmitt, Carla C. ^[1] ; Neumann, Miguel G. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY; v. 252, p. 124-130, JAN 15 2013.
• Citações Web of Science: 25

Resumo

The photoinitiator system Safranine/2-ethylaminodiphenylborinate (Sf/2APB) was used to polymerize HEMA and the kinetics of the reaction were followed by isothermal photocalorimetry. The active initiating radical is 2APB(center dot-), arising from the reaction of triplet Safranine with 2APB. The formation of a semioxidized form of Sf leads to photobleaching of the dye, which occurs with the same rate as polymerization, indicating that both species are formed simultaneously. When adding diphenyliodonium chloride (DPIC) to the photoinitiating mixture the polymerization rate is accelerated due to the reaction of the 2APB(center dot-) radical ion with DPIC to form Ph-center dot radicals. These radicals are about 7 times more efficient for polymerization than the boron centered radicals. Photobleaching of the dye is also inhibited by the addition of DPIC. (C) 2012 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 09/15998-1 - Interações de luz UV/visível com compósitos de polímero-argila: fotopolimerização e fotodegradação
• Beneficiário: Carla Cristina Schmitt Cavalheiro
• Modalidade de apoio: Auxílio à Pesquisa - Regular