POLY(HYDRAZIDE-ESTER)S AND POLY(1,3,4-OXADIAZOLE-ESTER)S CONTAINING PENDENT PHENOXY GROUPS

A series of new aromatic poly(hydrazide-ester)s has been synthesized b y solution polycondensation of two diacid dichlorides containing prefo rmed ester groups with phenoxyterephthaloyl dihydrazide or with a mixt ure of phenoxyterephthaloyl dihydrazide with terephthaloyl- or isophth aloyl dihydrazide in N-methyl-2-pyrrolidinone. The thermal cyclization of the poly(hydrazide-ester)s gave the corresponding poly(1,3,4-oxadi azole-ester)s containing pendent phenoxy groups. The polymers were cha racterized by viscometry, solubility measurements, IR spectroscopy, di fferential scanning calorimetry and thermogravimetric analysis.