New Organosoluble, Thermally Stable, and Nanostructured Poly(Amide-Imide)s with Dopamine Pendant Groups: Microwave-Assisted Synthesis and Characterization

We have developed facile and rapid polycondensation reactions of 3,5-diamino-N-(3,4-dihydroxyphenethyl)benzamide with several N,N′-(pyromellitoyl)-bis-L-α-amino acids, in the presence of small amount of a molten salt, tetrabutylammonium bromide, and triphenyl phosphite as the activator by using a domestic microwave oven. The polycondensation reactions proceeded rapidly, and completed within 4 min, to produce a series of novel chiral, thermally stable, and nanostructured poly(amide-imide)s (PAI)s in high yield with inherent viscosities of 0.43-0.52 dL/g. The resulting PAIs were characterized using FT-IR, 1H-NMR technique, elemental analysis, powder X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, and by measuring their viscosities, specific rotations, and solubilities.