Reaction of Isocyanates with Cyclic Anhydrides

Isocyanates react with cyclic anhydrides to form cyclic imides [1, 3, 15]  

Primary Secondary Primary Secondary aliphatic aliphatic aromatic aromatic amine amine amine amine 

Primary hydroxyl groups are more reactive than secondary hydroxyl groups and much more reactive than tertiary or phenolic hydroxyl groups  

In order to understand the effect of polyol structure on the properties of polyurethanes a minimum amount of information about the structure and reactivity of isocyanates is 

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