AbstractDiisocyanates condense readily with hydrazine or hydrazine hydrate to give polyureylenes with the structure:documentclass{article}pagestyle{empty}begin{document}$$ left hbox{---} {rm R} hbox{---} {rm NHCONHNH} hbox{---} {rm CONH} hbox{---} right_x $$end{document}Similarly, dihydrazides (NH2NHCOR′CONHNH2) condense with diisocyanates to give polymers with the structure:documentclass{article}pagestyle{empty}begin{document}$$ left hbox{---} {rm R} hbox{---} {rm NHCONHNH} hbox{---} {rm COR'} hbox{---} {rm CONHNHCONH} hbox{---} right_x $$end{document}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 unsuccess
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