Synthesis and properties of novel soluble polyamides containing both fluorene or xanthene cardo moieties and fluorinated phenoxy pendant groups

A series of novel aromatic polyamides containing both fluorene or xanthene cardo moieties and fluorinated phenoxy pendant groups were synthesized from two fluorinated isophthaloyl chlorides and four diamines containing cardo groups by the low‐temperature solution polycondensation in N,N‐dimethylacetamide (DMAc). The obtained polymers were characterized by different physicochemical techniques. All the polymers were amorphous and readily soluble in many organic solvents such as DMAc, N‐methyl‐2‐pyrrolidinone, N,N‐dimethylformamide, dimethyl sulfoxide, pyridine, and tetrahydrofuran at room temperature. The new fluorinated polyamides had high thermal stability with the glass transition temperatures of 237–259°C, the temperatures at 5% weight loss of 437–476°C in nitrogen. All the polymers formed transparent, strong, and flexible films with tensile strengths of 70.6–87.5 MPa, tensile moduli of 2.23–2.78 GPa, and elongations at break of 5.8–8.7%. These polyamide films had high optical transparency with an ultraviolet–visible absorption cutoff wavelength of 352–368 nm, low dielectric constants of 3.24–3.45 (1 MHz), and lower water absorptions of 1.06–1.43%. POLYM. ENG. SCI., 57:1234–1241, 2017. © 2017 Society of Plastics Engineers