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A novel, fluorinated diamine monomer, 2,5-bis(4-amino-2-trifluoromethylphenoxy)-tert-butylbenzene (II) was synthesized through the nucleophilic substitution reaction of tert-butylhydroquinone (t-BHQ) 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 diamine II. A series of fluorinated polyimides V were prepared from II with various aromatic dianhydrides (III a-f ) via the thermal imidization of poly(amic acid). Most of V a-f could be soluble in amide-type solvents and even in less polar solvents. These polyimide films showed tensile strengths up to 106 MPa, elongation at break up to 21%, and initial modulus up to 2.1 GPa. The glass-transition temperature of V was recorded at 245-304°C, the 10% weight loss temperatures were above 488°C, and left more than 41% residue even at 800°C in nitrogen. Low dielectric constants, low moisture absorptions, and higher and light-colored transmittances were also observed.

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