POLYISOPHTHALAMIDES WITH PENDENT HETEROCYCLIC GROUPS .3. PYRIDINE PENDENT GROUPS

A series of polyisophthalmides (PIPAa) containing pendent isonicotinam ido groups has been prepared from six aromatic diamines and a novel mo nomer, 5-(isonicotinoylamino)isophthalic acid. These polymers, which s hould be considered as modified PIPAs, have high inherent viscosities (about 1.0 dl g(-1)) and are synthesized in high yields by the phospho rylation polycondensation method. They show a better solubility in org anic polar solvents than the parent unmodified polyisophthalamides, an d their glass transition temperatures are 20-30 degrees C higher. Howe ver, 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 m uch water by weight as conventional PIPAs. Equilibrium water absorptio n of up to 17% can be measured for some samples.