Synthesis and properties of new triphenylamine-containing aromatic polyimides based on N,N′-bis(4aminophenyl)-N,N′-diphenyl-4,4′-biphenyldiamine

A new aromatic diamine monomer, N,N'-bis(4-aminophenyl)-N,N'-diphenyl-4,4'-biphenyl-diamine, was first synthesized in two steps by the condensation of N,N'-diphenyl-4,4'-biphenyldiamine with 4-fluoronitrobenzene, followed by reduction. New triphenylamine-containing aromatic polyimides having inherent viscosities of 0.67-0.91 dl g(-1) were synthesized from the aromatic diamine and various aromatic tetracarboxylic dianhydrides by the conventional two-step procedure that included ring-opening polyaddition giving precursor polyamic acids and subsequent thermal cyclodehydration. Most of the aromatic polyimides were soluble on heating in organic solvents such as dimethylacetamide, m-cresol, pyridine, and chloroform, and gave flexible and tough films with good tensile properties. The glass transition temperatures and 10% weight loss temperatures of the polyimides were in the range of 293-361 and 565-595 degreesC, respectively, in nitrogen.