Synthesis and characterization of new polyamide-imides containing pendent adamantyl groups

A new diimide-dicarboxylic acid, 4-(1-adamantyl)-1,3-bis(4-trimellitimidophenoxy)benzene (ADBTB), containing pendent adamantyl group was synthesized in three steps starting from adamantyl resorcinol. A series of new adamantyl-containing polyamide-imides (PAIs) were prepared by direct polycondensation of ADBTB and various aromatic diamines in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. These PAIs produced had inherent viscosities of 0.72–0.94 dl g−1. All the PAIs were readily dissolved in various solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, pyridine, cyclohexanone and tetrahydrofuran. These PAIs were solution-cast from DMAc solutions into transparent, flexible, and tough films except for PAI-5 polymer film. Wide-angle X-ray measurement revealed that all the polymers were amorphous. These PAIs had glass transition temperatures between 230–254°C and 10% weight loss temperatures in the range of 467–491°C in nitrogen atmosphere. The polymer films had a tensile strength range of 67–110 MPa and a tensile modulus range of 2.1–2.6 GPa.