AROMATIC POLYAMIDES WITH BENZOTHIAZOLE PENDENT GROUPS - SYNTHESIS, NUCLEAR-MAGNETIC-RESONANCE STRUCTURAL STUDY AND EVALUATION OF PROPERTIES

A new family of aromatic polyamides were prepared from six aromatic di amines and a new monomer derived from isophthalic acid: 5-(2-benzothia zolyl)isophthaloyl chloride. Theoretical calculations of the reactivit y of the new monomer were made by semiempirical methods. The polymers were synthesized by the solution polycondensation method at low temper ature, in high yields and moderate to high inherent viscosities. The p resence of pendent benzothiazole rings brought about remarkable change s in the spectral (nuclear magnetic resonance) characteristics, compar ed with those of the homologous unmodified polyisophthalamides. Notice able improvements were observed also for the solubility and for the gl ass transition temperatures, which rose 20-30-degrees-C relative to th ose of the conventional polyisophthalamides. Thermogravimetric analyse s showed that the new polymers have better thermal stability than the unmodified ones.