Structure–Property Relations in Oligomers of Linear Aliphatic Diisocyanates

Oligomerization reactions of aliphatic diisocyanates, exclusively involving NCO groups are discussed. The reactivity and selectivity of these reactions are dependent on chain length, reaction conditions, and the catalyst employed. The resulting oligomers (“dimers” and “trimers”) sometimes deviate considerably from expectation with respect to the structure and properties. The synthesis and characterization of well-known derivatives such as uretdiones and isocyanurates are discussed, and special attention is devoted to the recently developed iminooxadiazinedione chemistry. Finally, a new class of compounds is introduced, the tricyclic diiminooxadiazinones.