Organosoluble and colorless fluorinated poly(ether imide)s from 1,2-bis(3,4-dicarboxyphenoxy)benzene dianhydride and trifluoromethyl-substituted aromatic ris(ether amine)s

A series of novel aromatic poly(ether imide)s (PEI) containing ortho-catenated phenylene rings and pendant trifluoromethyl group have been prepared from 1,2-bis(3,4-dicarboxyphenoxy)benzene dianhydride (1) with seven trifluoromethyl-substituted aromatic bis(ether amine)s (2a-g) via a conventional two-stage process that included ring-opening polyaddition to form the poly(amic acid)s followed by chemical imidization to the polyimides. These PEIs had inherent viscosities in the range of 0.45-1.17 dL/g that corresponded to weight-average and number-average molecular weights (by gel-permeation chromatography) of 42,000-102,000 and 28,500-67,500, respectively. All the PEls were readily soluble in many organic solvents and could be solution-cast into transparent, flexible, and strong films. These films were essentially colorless; they had a very low yellowness index of 4.34-6.55 and an UV-vis absorption cut-off wavelength at 361-370 nm. The PEls exhibited moderate-to-high glass-transition temperatures (T-g) in the range of 185-270 degrees C, softening temperatures (T-S) in the range of 184-275 degrees C, and 10% weight loss temperatures higher than 466 degrees C in nitrogen or in air. They also showed low moisture absorptions of 0.49-0.70% and low dielectric constants of 2.78-3.26 (measured at 10 kHz). (c) 2006 Wiley Periodicals, Inc.