SYNTHESIS AND CHARACTERIZATION OF 3,6-DIAMINOACRIDINE (PROFLAVINE) CONTAINING POLYIMIDES

The tricyclic heterocyclic molecule 3,6-diaminoacridine (proflavine) has been reacted with the dianhydrides pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), and naphthalenetetracarboxylic dianhydride (NTCDA) to yield a new series of polyimides in which the aromatic tricyclic clic component contains a ring nitrogen atom at position 10. The synthesis of the four polymers was achieved within; the temperature range of 185-195 degrees C and each of the polyimides was characterized with respect to solubility, thermal-properties; infrared and W-visible spectra, refractive index, and permittivity. Uniform, light yellow films of the four polyimides could be cast from appropriate solvents. TGA analysis of these polyimides showed that they were thermally stable up to 600 degrees C in a nitrogen atmosphere. These polymers exhibited low permittivity values and high refractive indices. All four;polymers were soluble in dilute formic acid, in addition to several common organic solvents. Formic acid solutions of the polyimide from 3,3',4,4'-benzophenonetetracarboxylic dianhydride and proflavine exhibited birefringent behavior. upon orientation by repeated passage through a viscometer capillary. In contrast to the polymer prepared from 3,7-diaminophenothiazine (thionine) and pyromellitic dianhydride, in which the intermediate poly(amic acid) could be isolated nd characterized, the reaction of proflavine and pyromellitic dianhydride did not proceed at sufficiently low temperatures to permit the isolation of the intermediate poly(amic acid).