Amine-Functional Silicones

Aminoalkyl-functional silicones have a broad array of applications as a result of their chemical reactivity, their ability to form  hydrogen bonds and, particularly in the case of diamines, their chelating ability. Additional reactivity can be built into aminoalkyl  groups in the form of alkoxygroups. Aminoalkylsiloxanes are available in the three classes of structures typical for silicone polymers: terminated, pendant group, and T-structure.

Aminopropyl-terminated polydimethylsiloxanes react to form a variety of polymers including polyimides, polyureas,¹ and  polyurethanes. Block polymers based on these materials are becoming increasingly important in microelectronic (passivation  layer) and electrical (low-smoke generation insulation) applications. They are also employed in specialty lubricant and surfactant  applications. Phosphorylcholine derivatives have been utilized as coatings for extended-wear contact lenses.²

Amino-functionality pendant from the siloxane backbone is available in two forms: (aminopropyl)-methylsiloxane-dimethylsiloxane copolymers and (aminoethylaminopropyl)-methylsiloxane-dimethylsiloxane copolymers. They are frequently  used in modification of polymers such as epoxies and urethanes, internal mold releases for nylons and as lubricants, release agents, and components in coatings for textiles and polishes.

Aminoalkyl T-structure silicones are primarily used as surface treatments for textiles and finished metal polishes (e.g. automotive  car polishes). The resistance to wash-off of these silicones is frequently enhanced by the incorporation of alkoxy groups which  slowly hydrolyze and form crosslink or reactive sites under the influence of the amine. The same systems can be reacted with  perfluorocarboxylic acids to form low surface energy (<7 dynes/cm) films.³

1. Riess, C. Monatshefte Chem. 2006, 137, 1434.
2. Willis, S. et al Biomaterials, 2001, 22, 3261.
3. Thürman, A. J. Mater. Chem. 2001, 11, 381.