Synthesis and Characterization of New Soluble Polyamides from 9,9-Bis[4-(chloroformylphenoxy)phenyl]xanthene and Various Aromatic Diamines

9,9-Bis(4-hydroxyphenyl)xanthene (BHPX) was synthesized in 82% yield from xanthenone in a one-pot, two-step synthetic procedure. A new diacyl chloride monomer, 9,9-bis[4-(chloroformylphenoxy)phenyl]xanthene (BCPX), was synthesized in three steps from the nucleophilic fluorodisplacement of 4-fluorobenzonitrile with the dipotassium bisphenolate of BHPX, followed by alkaline hydrolysis of the intermediate bis(ether nitrile), and then chlorination with thionyl chloride. Several novel aromatic polyamides containing ether and bulky xanthene groups with the inherent viscosities (0.72-0.98 dL/g) were prepared by the low temperature polycondensation of BCPX with various aromatic diamines in N,N-dimethylacetamide (DMAc) solution containing pyridine (Py). All new polyamides were amorphous and readily Soluble in various polar solvents such as DMAc, N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and Py. These polymers showed relatively high glass transition temperatures between 236 and 298 degrees C, decomposition temperatures at 10% weight loss ranging from 490 to 535 degrees C and 483 to 515 degrees C in nitrogen and air, respectively. and char yields at 700 degrees C in nitrogen higher than 50%. Transparent, flexible, and tough films of these polymers cast from DMAc solutions exhibited tensile strengths ranging from 82 to 106 MPa, elongations at break from 10% to 25%, and initial moduli from 2.0 to 2.8 GPa.