Novel soluble fluorinated aromatic polyamides derived from 2-(4-trifluoromethylphenoxy)terephthaloyl chloride with various aromatic diamines

A series of novel fluorinated aromatic polyamides derived from a new monomer, 2-(4-trifluoromethylphenoxy)terephthaloyl chloride (TFTPC), with various aromatic diamines were synthesized and characterized. The polyamides were obtained in high yields and moderately high inherent viscosities ranging from 1.07 to 1.16 dL/g. All the polyamides were amorphous and readily soluble in many organic solvents, such as N-methyl-2-pyrrolidinone (NMP), N,N′-dimethylacetamide (DMAc), N,N′-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and could afford flexible and tough films via solution casting. The cast films exhibited good mechanical properties with tensile strengths of 82.8–107.3 MPa, elongation at break of 4.1–7.2%, and tensile modulus of 2.26–3.95 GPa. These polyamide films also exhibited good thermal stability with the glass transition temperature of 222–294 °C, the temperature at 5% weight loss of 442–472 °C in nitrogen. They exhibited low dielectric constants ranging from 3.25 to 3.39 (1 MHz), low moisture absorption in the range of 1.32–2.45%, high transparency with an ultraviolet–visible absorption cut-off wavelength in the 330–371 nm range, and excellent electrical properties.