Synthesis and characterization of fluorinated polyimide oligomers terminated with a phenylethynyl group

Abstract

Novel all-aromatic phenylethynyl-terminated imide oligomers were prepared by the reaction of 4,4-oxydiphthalic anhydride (ODPA) or 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) with 1,4-(4-amino-2-trifluoromethyl-phenoxy)-2-(3′-trifluoro-methylphenyl) benzene and 4-(1-phenylethynyl)1,8-naphthalic anhydride (PENA). The resulting polymers were thermally crosslinked at 370°C. The cured polymers exhibited good solvent resistance and high thermal stability up to 540°C under nitrogen. They also exhibited small light absorption at 1.31 and 1.55μm. The refractive index of the polymers was in the range of 1.5515–1.5976 at 1550nm. The surface relief depth of the phenylethyl terminated imide (PETI) oligomer films before and after curing was less than 1nm over a range of 1μm×1μm.