Chin‐Ping Yang, Yu-Yang Su, Feng-Zhi Hsiao
Oct 13, 2004
Citations
1
Influential Citations
46
Citations
Journal
Polymer
Abstract
Abstract New aromatic diamine with cyclohexane cardo group substituted with trifluoromethyl group in the side chain, 1,1-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]cyclohexane ( II ), was prepared through the nucleophilic substitution reaction of 1,1-bis(4-hydroxyphenyl)cyclohexane and 2-chloro-5-nitrobenzotrifluoride in the presence of potassium carbonate, to yield the intermediate dinitro compound I , followed by catalytic reduction with hydrazine and Pd/C to afford the diamine II . Fluorinated polyimides ( IVa–g ) were prepared from the II with various aromatic dianhydrides via thermal or chemical imidization of poly(amic acid). These polyimides had inherent viscosity ranging from 0.72 to 1.16 dl/g and showed excellent solubility in a variety of organic solvents. They were soluble in a concentration of 10% in the amide polar solvent, and 1–5% in the other testing solvents. IV films showed good mechanical properties, excellent thermal stability. The 10% weight loss temperature was above 476 °C in nitrogen or air, and the glass transition temperature was recorded at 214–278 °C. In comparison of the IV series with the analogous nonfluorinated polyimides ( V series) based on 1,1-bis[4-(4-aminophenoxy)phenyl]cyclohexane ( II′ ), IV series revealed better solubility, lighter-colored and lower dielectric constants and moisture absorptions. Their films had cut-off wavelengths in the range of 364–414 nm, b * value (a yellowness index) ranging from 3.3 to 66.3, dielectric constants of 3.02–3.55 (1 MHz), with moisture absorption of 0.16–0.36 wt%.