Renewable and water-degradable polyimide-esters from citric acid

Citric acid is an abundant, naturally occurring small molecule that affords a cyclic imide when condensed with a primary amine. The reaction of a reduced derivative of citric acid and glycine yields a cyclic imide diacid. This monomer was copolymerized with a variety of linear diols and sugar-derived diols, yielding copolymers with a tunable glass transition temperature ranging from T_g = 25 to 134 °C. Unlike most polyesters, these polyimide-esters hydrolyze under environmentally-relevant conditions and thus, show promise as sustainable replacements for high T_g commodity plastics.