POLYISOPHTHALAMIDES WITH PENDENT HETEROCYCLIC GROUPS .3. PYRIDINE PENDENT GROUPS

A series of polyisophthalmides (PIPAa) containing pendent isonicotinamido groups has been prepared from six aromatic diamines and a novel monomer, 5-(isonicotinoylamino)isophthalic acid. These polymers, which should be considered as modified PIPAs, have high inherent viscosities (about 1.0 dl g(-1)) and are synthesized in high yields by the phosphorylation polycondensation method. They show a better solubility in organic polar solvents than the parent unmodified polyisophthalamides, and their glass transition temperatures are 20-30 degrees C higher. However, the thermal stability, as measured by thermogravimetric analysis, is lower, showing initial thermal decomposition temperatures of about 400 degrees C. These novel PIPAs can take up approximately twice as much water by weight as conventional PIPAs. Equilibrium water absorption of up to 17% can be measured for some samples.