Polyimine

Polyimines can be synthesised via a condensation reaction between aldehydes and (primary) amines. During this reaction, water is also formed as byproduct. Often, the synthesis can be performed at room temperature, but to fully cure the materials and remove remaining water, they can be dried at slightly elevated temperatures and/or in vacuum. and cadaverine. ==Applications==

One of the applications of polyimines is as in covalent adaptable networks (CANs). These are polymer materials that are crosslinked via dynamic covalent bonds. Besides polyimines, other types of dynamic covalent chemistry can also be used. Polyimine CANs are largely investigated to create recyclable and self-healing thermoset materials, but they can also find use in composite materials with higher performance. Flame retardants Because of the free radical scavenging properties of imines, they are well fit to be used in flame retardant materials. In addition, different polyimine materials have also been investigated for which phosporous species have been incorporated. These materials represent more sustainable and less harmful alternatives to previously used halogenated polymers. Sensory devices The dynamic characteristics of polyimines enables them to be used as sensory devices. An example of this is the sensing of amine compounds. Polyimine materials have been constructed that enable penetration of (small) monoamine molecules.{{Cite journal|last1=Kathan|first1=M.|last2=Jurissek|first2=C.|last3=Kovaříček |first3=P.|last4=Hecht|first4=S.| title=Imine-based dynamic polymer networks as photoprogrammable amine sensing devices|journal= Journal of Polymer Science Part A: Polymer Chemistry|year=2019|volume=57|issue=24|pages=2378–2382|doi=10.1002/pola.29518 Electronic skin Polyimines have been investigated for their use in the production of electronic skins (e-skin).{{Cite journal|last1=Zou|first1=Z.|last2=Zhu|first2=C.|last3=Li |first3=Y.|last4=Lei|first4=X.|last5=Zhang|first5=W.|last6=Xiao|first6=J.| title=Rehealable, fully recyclable, and malleable electronic skin enabled by dynamic covalent thermoset nanocomposite|journal=Science Advances|year=2018|volume=4|issue=2|article-number=eaaq0508|doi=10.1126/sciadv.aaq0508 ==Bio-based polyimines==

Various studies have been conducted to synthesise bio-based polyimines due the great natural abundance of aldehydes and amines.{{Cite journal|last1=Liguori|first1=A.|last2=Hakkarainen|first2=M.| title=Designed from Biobased Materials for Recycling: Imine-Based Covalent Adaptable Networks| journal = Macromolecular Rapid Communications ==Imines in other polymers==

Apart from polyimine polymers that are formed directly via the condensation reaction from aldehydes and amines, it is also possible to incorporate imines in other existing polymer materials. Imines have, for example, been incorporated into recyclable epoxy-based thermosets and polyesters. ==Confusion in nomenclature==

Polyimines are commonly abbreviated as PI. However, the same abbreviation is typically used for polyimide. Which has almost the same name, but is a significantly different type of polymer material. Sometimes the term polyimine is used to describe a material called polyethyleneimine. This material exists in different forms (i.e., linear or branched), but does in fact not contain actual imine (C=N) bonds. ==See also==