Soluble, Rigid-Rod Polyamide, Polyimides, and Polyazomethine with Phenyl Pendent Groups Derived from 4,4‘‘-Diamino-3,5,3‘‘,5‘‘-tetraphenyl-<i>p</i>-terphenyl

Abstract

The reaction of 4,4‘-(1,4-phenylene)bis(2,6-diphenylpyrylium tetrafluoroborate) with nitromethane afforded 4,4‘‘-dinitro-3,5,3‘‘,5‘‘-tetraphenyl-p-terphenyl, which was catalytically hydrogenated to the corresponding diamine. The latter was used as starting material for the preparation of new rigid-rod polyamide, polyimides, and polyazomethine bearing phenyl pendent groups as well as the respective model compounds. Characterization of polymers was accomplished by inherent viscosity measurements, elemental analysis, 1H-NMR, 13C-NMR, X-ray, DTA, TMA, TGA, and isothermal gravimetric analysis. The polymers were amorphous and soluble in polar aprotic solvents. Polyamide showed an outstanding solubility, being soluble even in o-dichlorobenzene and chloroform. Polyamide displayed Tg and softening temperature at 135 and 155 °C, respectively, whereas other polymers showed only Tg above 265 °C. The polymers were stable up to 397−441 °C in N2 and 344−363 °C in air and afforded anaerobic char yields of 68−77% at 800 °C. In addition, the thermal stability of polyazomethine was investigated as a function of the curing time.