Synthesis and characterization of novel polyamides derived from 1,4-bis((4-amino-2-(trifluoromethyl)phenoxy)methyl)cyclohexane and aromatic dicarboxylic acids

A new aromatic diamine with a trifluoromethyl pendent group, 1,4-bis((4-amino-2-(trifluoromethyl)phenoxy)methyl)cyclohexane, was successfully synthesized in two steps from 1,4-cyclohexanedimethanol and 2-chloro-5-nitrobenzotrifluoride as starting materials. And the newly obtained diamine with various aromatic dicarboxylic acids, including isophthalic acid (IPA), 2,2-bis(4-carboxy-phenyl)hexafluoropropane (6FA) and 4,4'-oxydibenzoic acid (OBA), were polymerized, respectively via the usual Yamazaki reaction to prepare a series of fluorinated polyamides. The resulting polymers had inherent viscosities ranging from 1.85 to 2.36 dL/g. All the polymers showed outstanding solubility and could be easily dissolved in amide-type polar aprotic solvents [e.g., N-methyl-2-pyrrolidone (NMP), DMAc, and DMF] and even dissolved in less polar solvents (e.g., pyridine, and tetrahydrofuran). These polymers could also be easily be cast into transparent, tough and flexible films with tensile strengths of 76.5-82.3 MPa, Young's moduli of 1.64-1.85 GPa, and elongations at break of 10-12%. In addition, these polyamides films exhibited low dielectric constants of 2.37-2.53 at 100 MHz, low water absorptions in the range of 1.54-2.13%, and high transparency with an ultraviolet-visible absorption cut-off wavelength in the 326-333 nm range. Furthermore these polyamides still retained good thermal stability. These combined outstanding features make these obtained polyamides competitive for advanced microelectronic applications.