Organosoluble, low-dielectric-constant fluorinated polyimides based on 2,6-bis(4-amino-2-trifluoromethyl phenoxy) naphthalene

A novel fluorinated bis(ether amine) monomer, 2,6-bis(4-amino-2-trifluoromethylphenoxy) naphthalene, was prepared through the nucleophilic aromatic substitution reaction of 2-chloro-5-nitrobenzotrifluoride and 2,6-dihydroxynaphthalene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of novel trifluoromethylated polyimides were synthesized from the diamine with various commercially available aromatic tetracarboxylic dianhydrides using a two-stage process with thermal imidization of poly(amic acid) films. Most of the resulting polyimides were highly soluble in a variety of organic solvents and could afford transparent and tough films via solution casting. These polyimides exhibited moderately high glass transition temperatures (T(g)s) of 249-311 degreesC, high thermal stability and good mechanical properties. Low moisture (0.19-0.85%), low dielectric constants (2.49-3.59 at 10 kHz), and low color intensity were also observed. For a comparative study, a series of analogous polyimides based on 2,6-bis (4-aminophenoxy) naphthalene were also prepared and characterized. (C) 2005 Society of Chemical Industry.