polyimine

Polyimine refers to polymers in which repeating units incorporate imine linkages (-C=N-). These linkages form by condensation of primary amines with carbonyl groups such as aldehydes or ketones. Polyimines belong to the class of dynamic covalent polymers, with imine bonds that can undergo reversible exchange (transimination). This reversibility enables reconfiguration, self-healing, and potential recycling of the material.

Synthesis commonly involves combining difunctional amines with difunctional carbonyl compounds to yield crosslinked networks or linear polymers. The reaction can occur at ambient temperature in common solvents, and network properties are tuned by the choice of monomers and crosslink density. In many systems, water is produced during imine formation, and bond exchange can be accelerated by heat or catalysts.

The performance of polyimines depends on monomers and environment. Imine bonds are relatively stable in dry, neutral conditions but are susceptible to hydrolysis in the presence of water or acids, which permits reversible remodeling of the network. Thermal or catalytic conditions can promote bond exchange, enabling reprocessing and self-healing, though long-term stability may be lower than that of conventional thermosets.

Applications include self-healing coatings, recyclable or reprocessable thermosets, adhesive systems, flexible membranes, and hydrogels for sensing or actuation. The dynamic nature of the imine bond makes polyimines attractive for sustainable materials and rapid prototyping, though moisture sensitivity and chemical stability remain active areas of study.