Unhindered aldimines tend to cyclize, as illustrated by the condensation of methylamine and formaldehyde, which gives the hexahydro-1,3,5-triazine.
Imine polymers (polyimines) can be synthesised from multivalent aldehydes and amines. The polymerisation reaction proceeds directly when the aldehyde and amine monomers are mixed together at room temperature. In most cases, (small) amounts of solvent may still be required. Polyimines are particularly interesting materials because of their application as vitrimers. Owing to the dynamic covalent nature of the imine bonds, polyimines can be recycled relatively easily. Furthermore, polyimines are known for their self-healing behaviour.