Polyamidoamines (PAMAM)

Properties and Applications

Polyamidoamines are liquid amides having multiple amine functionalities. They are synthesized by amidation of esters or acids with amines. The most common class of polyamidoamines are products of (bio-based) dimerized fatty acids and aliphatic polyamines. This type of polyamidoamine is mainly used as a high molecular weight, reactive epoxy curing agent.¹ They often improve the water and corrosion resistance as well as the flexibility and toughness of polyepoxides (epoxies). Other benefits include longer pot life, superior metal adhesion and pigment wetting. Polyamidoamines are often combined with other curing agents because they reduce the heat resistance and mechanical strength due to the reduced crosslink density.
Important applications for polyamidoamides include adhesives, coatings, inks, putties, sealants, and potting compounds

Another noteworthy class of polyamidoamines are  Starburst dendrimers.² They are synthesized by sequential Michael addition of α,β-unsaturated esters/acids to amines followed by amidation. This type of polyamidoamine consists of an ethylenediamine core, a repetitively branched amidoamine shell, and a surface layer of terminal primary amines. They differ from ordinary polymers in that they have a well defined structure and molecular weight. Their properties are very different from those of the corresponding linear analog and are typically dominated by the functional groups on the surface. The high density of exterior functional groups provides multiple interactions with other molecules and (nano) particles.
PAMAM dendrimers are used as compatibilizers, stabilizers, protective agents, and controlled release additives. Important applications include (controlled) drug delivery systems (encapsulation of drugs), personal care products, cosmetics, and inks.

Manufacturers & Distributors

¹US Patent 8,293,863 B2, Polyamide curative from substituted amine and dimer fatty acid or ester
²Starburst is a trademark of the Dow Chemicals Company.