New aromatic polyimides containing triphenylamine unit were prepared by two different methods, i.e., a conventional two‐step method starting from 4,4′‐diaminotriphenylamine and aromatic tetracarboxylic dianhydrides and the one‐step thioanhydride method starting from the aromatic diamine and aromatic tetracarboxylic dithioanhydrides. Both procedures yielded high‐molecular‐weight polyimides with inherent viscosities of 0.47–1.17 dL/g. Some of these polymers were soluble in organic solvents such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, m‐cresol, and pyridine. All the polyimides afforded transparent, flexible, and tough films, and the color varied from pale yellow to dark red, depending markedly on the tetracarboxylic acid components. The glass transition temperatures (Tgs) of these polyimides were in the range of 287–331°C and the 10% weight loss temperatures were above 520°C in air. The polyimides prepared by the one‐step method exhibited better solubility in organic solvents and had somewhat lower Tgs than the polymers prepared by a conventional two‐step method.

A new triphenylamine-containing aromatic diamine, N,NЈ-bis(4-aminophenyl)-N,NЈ-diphenyl-1,4-phenylenediamine, was prepared by the condensation of N,NЈdiphenyl-1,4-phenylenediamine with 4-fluoronitrobenzene, followed by catalytic reduction. A series of novel aromatic polyamides with triphenylamine units were prepared from the diamine and various aromatic dicarboxylic acids or their diacid chlorides via the direct phosphorylation polycondensation or low-temperature solution polycondensation. All the polyamides were amorphous and readily soluble in many organic solvents such as N,N-dimethylacetamide and N-methyl-2-pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with relatively high glass-transition temperatures (257-287°C), 10% weight-loss temperatures in excess of 550°C, and char yields at 800°C in nitrogen higher than 72%.

Polyimides prepared from 4,4' -diaminotriphenylamine (DATPA) had fairly large fraction of free space VF among unfiuorinated polyimides because of hindrance effect of phenyl side-groups on packing of the polymer chains. Due to the fairly large VF, they displayed fairly high gas permeability. For H 21CH4 and C021CH4 systems, they had lower permselectivity as compared with the other polyimides having the similar permeability coefficients for a higher permeable gas, because of lower diffusivity selectivity attributed probably to rotational motion of phenyl side-groups. On the other hand, for C0 2 IN2 and 0 2 IN2 systems, they had moderate levels of the permselectivity, because rotational motion of phenyl side-groups affected slightly on the diffusivity selectivity of these gas pairs with very small differences in the effective molecular size.

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