Pyrromethene derivatives as photoinitiators in free radical photopolymerization

OLGA I. TARZI; CHRISTIAN LEY; XAVIER ALLONAS; JEAN PIERRE FOUASSIER

Florianópolis, Brasil

Conferencia; 10a Conferencia Latinoamericana de Físco Química Orgánica; 2009

Comité Organizador

Besides from being well known solid-state laser dyes, pyrromethenes have shown very good performance as sensitizing dyes in photopolymerization. In this study, 1,3,5,7,8-pentamethyl pyrromethene BF2 complex (HMP, 1) and 2,6-diethyl-8-phenyl-1,3,5,7-tetramethylpyrromethene BF2 complex (EPP, 2) were used to polymerize a diacrylate in a two and a three component system, together with an amine (3) and a triazine (4). For both pyrromethenes, the highest conversion was achieved with the three component photoinitiating system. As these dyes have high fluorescence quantum yields, steady state and time resolved techniques were used to study the possible fluorescence quenching by the amine and the triazine. The electron transfer process that occurs in these photoinitiating systems was evidenced through time-resolved photoconductivity and laser flash photolysis experiments.