Condensation polymers from diisocyanates with dihydrazides and hydrazine

Diisocyanates condense readily with hydrazine or hydrazine hydrate to give polyureylenes with the structure: Similarly, dihydrazides (NH2NHCOR′CONHNH2) condense with diisocyanates to give polymers with the structure: Tough films and fibers can be prepared from these polymers by conventional techniques. Solutions of some of these polymers are relatively unstable at elevated temperatures, the polymer apparently reverting to starting materials. Attempts to stabilize the solutions were unsuccessful.