Organosoluble and light-colored fluorinated polyimides based on 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl] propane and aromatic dianhydrides

摘要

A novel fluorinated diamine monomer, 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]propane (2), was prepared through the nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride with 2,2-bis(4-hydroxyphenyl)propane in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. Polyimides were synthesized from diamine 2 and various aromatic dianhydrides 3a-f via thermal imidization. These polymers had inherent viscosities ranging from 0.73 to 1.29 dL/g. Polyimides 5a-f were soluble in amide polar solvents and even in less polar solvents. These films had tensile strengths of 87-100 kWa elongations to break of 8-29%, and initial moduli of 1.7-2.2 GPa. The glass transition temperatures (T-g) of 5a-f were in the range of 222-271degreesC, and the 10% weight loss temperatures (T-10) of them were all above 493degreesC. Compared with polyimides 6 series based on 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) and polyimides 7 based on 2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (6FBAPP), the 5 series showed better solubility and lower color intensity, dielectric constant, and lower moisture absorption. Their films had cutoff wavelengths between 363 and 404 nm, b* values ranging from 8 to 62, dielectric constants of 2.68-3.16 (1 MHz), and moisture absorptions in the range of 0.04-0.35 wt %. (C) 2004 Wiley Periodicals, Inc.