Soluble and Colorless Poly(ether‐imide)s Based on a Benzonorbornane Bis(ether anhydride) and Trifluoromethyl‐Substituted Aromatic Bis(ether‐amine)s

Abstract

AbstractSummary: A series of organosoluble and colorless fluorinated poly(ether imide)s (IVa‐g) were prepared from 3,6‐bis(3,4‐dicarboxyphenoxy)benzonorbornane dianhydride (I) and various trifluoromethyl (CF3)‐substituted aromatic bis(ether amine)s IIa‐g by a standard two‐step process with thermal and chemical imidization of poly(amic acid) precursors. These poly(ether imide)s had inherent viscosities of 1.02–1.28 dL · g−1 and showed excellent solubility in many organic solvents. They could be solution‐cast into transparent, flexible, and tough films with good mechanical properties. These films were virtually colorless, with an ultraviolet‐visible absorption edge of 372–381 nm and a very low b* value (a yellowness index) of 10.8 to 18.2. The glass‐transition temperatures (Tg) and softening temperatures (Ts) were recorded between 216–292 °C and 209–285 °C, respectively. The decomposition temperature for 10% weight loss all occurred above 472 °C in nitrogen and 481 °C in air, and the char yields at 800 °C in nitrogen were more than 51%. They also showed low dielectric constants of 2.84–3.58 (1 MHz) and moisture absorptions in the range of 0.05–0.19%. In comparison with analogous V series poly(ether imide)s without the CF3 substituents, the IV series ones showed better solubility, lower color intensity, and lower dielectric constants.A novel series of fluorinated poly(ether imide)s.magnified imageA novel series of fluorinated poly(ether imide)s.