LASER INDUCED CATIONIC POLYMERIZATION OF EPOXY RESINS USING 2, 6-DI(4′-METHOXYPHENYL) 4- PHENYLPYRYLIUM HEXAFLUOROANTIMONATE. EFFECT OF ALCOHOLS ON PHOTO AND THERMAL POLYMERIZATION.

抄録

Laser exposure (at 488nm) of 2, 6-di(4′-methoxyphenyl)-4-phenylpyrylium hexafluoroantimonate (Pyr) in cycloaliphatic epoxy resin (CY 179) caused partial polymerization at laser dosage of 1.4J/cm². Less reactive bisphenol-A epoxy (Epon 828) underwent partial polymerization at laser dosage of 7.0J/cm². More complete polymerization of Epon 828 was observed at the same dose in the presence of 1, 6 hexanediol. Direct interaction of alcohol with the pyrylium excited state was demonstrated by fluorescence quenching. A Stern-Volmer plot and determination of pyrylium excited state lifetime allowed calculation of the rate constant for this reaction. The value of 3.8x10⁸L equiv^-1s^-1 is indicative of an efficient interaction which is proposed to result in the photogeneration of protons. In contrast to the photochemical studies, thermally-induced polymerization of epoxy was not enhanced in the presence of alcohols.