Copolymers of tributyl citrate (TBC) and hexamethylenediamine (HMDA) were synthesized with a solvent-free condensation method with molar ratios of TBC to HMDA varying from 2:1 to 1:2. The reaction led to poly(succinimide-co-citramide) copolymers which were characterized by infrared and Raman spectroscopies, X-ray diffraction, and thermal analyses. Hydrolysis of the copolymers resulted in water soluble polycitramides with number averaged molecular weights ranging from 1.16 x 104 to 5.00 x 103 as determined by gel permeation chromatography. 1H, 13C, and 13C-1H-heteronuclear single quantum coherence NMR spectroscopy has confirmed that the hydrolyzed polycitramides with COOH side chains and amide backbones are structurally similar to biodegradable poly(aspartic acid) (PASP). Interestingly, the polycitramides showed Ca2+ and Pb2+ ion chelating capabilities higher than PASP, citric acidsorbitol copolymers, or conventional resins. Thus, the polycitramides offer promise as a totally new class of metal sequesters and renewable substitutes for PASP and poly(acrylic acid). (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012