Synthesis and characterization of new cardo polyamide-imides containing ether and tricyclo[5.2.1.02,6]decane groups

A new cardo diimide-dicarboxylic acid, 8,8-bis[4-(4-trimellitimidophenoxy)phenyl]tricyclo[5.2.1.0(2,6)]decane (BTPTD), containing an ether linkage and a tricyclo[5.2.1.0(2,6)]decane group was synthesized by condensation reaction of 8,8-bis[4-(4-aminophenoxy)phenyl]tricyclo[5.2.1.0(2,6)]decane with trimellitic anhydride. A series of new cardo polyamide-imides were prepared by direct polycondensation of BTPTD with various aromatic diamines in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. The polymers were produced with high yield and moderate to high inherent viscosities, i.e., of 0.73-1.36 dL.g(-1). Nearly all polymers are readily soluble in polar aprotic solvents such as NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide, dimethyl sulfoxide as well as less polar solvents such as pyridine, gamma-butyrolactone, and tetrahydrofuran. These polymers were solution-cast from DMAc solution into transparent, flexible, and tough films except for polymers 4a and 4b. Wide-angle X-ray measurement revealed that all polymers were amorphous. These polyamide-imides have glass transition temperatures between 250-290 degrees C and 5% weight loss temperatures in the range of 445 to 491 and 462 to 490 degrees C in nitrogen and air atmosphere, respectively. The polymer films have a tensile strength range of 77 to 87 MPa, an elongation at break range of 3 to 9%, and a tensile modulus range of 2.2 to 2.8 GPa.