polycarbodiimide

https://doi.org/10.1351/goldbook.15274
Polymer composed of macromolecules containing carbodiimide linkages in the backbone: \[\ce{-N=C=N\bond{-}}\]
Note: A polymer containing only pendent carbodiimide linkages is excluded.
Example:
polycarbodiimide
Source:
PAC, 2009, 81, 1131. (Glossary of class names of polymers based on chemical structure and molecular architecture (IUPAC Recommendations 2009)) on page 1153 [Terms] [Paper]