SYNTHESIS AND PROPERTIES OF IONIC, RIGID-ROD, AND THERMALLY STABLE POLYIMIDES CONTAINING BIPYRIDINIUM TRIFLATES

A series of nylene)bis(N-amino-2,6-diphenylpyridiniumtriflate) compoun ds were synthesized by reaction of 4,4'-(1,4-phenylene)bis(2,6-dipheny lpyrylium triflate) with various aromatic diamines. They were used as starting materials for the preparation of novel ionic rigid-rod polyim ides. The resulting poly(amic acid)s had inherent viscosities of 0.73- 1.93 dL/g. Thermal cyclodehydration of poly(amic acid)s afforded the p olyimides. Their inherent viscosities were in the range of 0.31-0.58 d L/g. These polyimides are basically amorphous and are soluble in polar aprotic solvents. A lyotropic behavior could be observed in a concent rated solution of dimethylformamide and methylpyrrolidone. Thermogravi metric analyses showed that they are thermally stable with 5% weight l osses recorded in the range of 459-478 degrees C under nitrogen and 46 9-489 degrees C in air. The polyimides had a tensile strength range of 59-93 MPa, and an elongation at break range of 5-9%. Reversibe color development of these polyimides could be observed upon irradiation in solution or in a polymer matrix.