Synthesis and Properties of New Triphenylamine-Containing Aromatic Polyimides Based on N,N′-Bis(4-Aminophenyl)-N,N′-Diphenyl-4,4′-Biphenyldiamine

A new aromatic diamine monomer, N,N′-bis(4-aminophenyl)-N,N′-diphenyl-4,4′-biphenyldiamine, 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 °C, respectively, in nitrogen.