Synthesis and Characterization of Polyimides Based on 6FAPE

One diamine,4,4-bis(4-amino-2-trifluoromethylphenoxy)diphenylether (6FAPE) is polymerized with five dianhydrides,1,2,3,4-cyclobutanetetracarboxylic (CBDA),3,3',4,4'-oxydiphthalic anhydride (ODPA),3,3',4,4'-biphenyltetracarboxylic acid dianhydride (BPDA),3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and pyromellitic dianhydride (PMDA) respectively,five kinds of fluorine-containing polyimides(PIs) are afforded by a two-step polycondensation procedure. The fluorine-containing PI films based on CBDA exhibit an excellent optical transparency in the visible wavelength region (400～700nm) with the transmittance higher than 84.6% at 450nm. The PI films show little absorption at the optocommunication wavelengths of 1.30μm and 1.55μm. Except for 6FAPE/CBDA,the fluorine-containing PIs show good thermal stability with the 5% thermal decomposing temperatures higher than 530℃ in nitrogen. The glass transition temperatures Tg of five kinds of fluorine-containing PI films are over 200℃,and PIs based on CBDA exhibit Tg higher than 265.5℃.