Naturally occurring tartaric acid was used as raw material for the synthesis of novel linear polyurethanes (PURs) bearing two carboxylate side-groups in the repeating unit. Aliphatic and aromatic PURs were obtained by reaction in solution of alkyl and benzyl tartrates with hexamethylene diisocyanate and 4,4'-methylene-bis(phenyl isocyanate), respectively. All the novel PURs were thermally stable and optically active. The aliphatic carboxylate-containing PURs had M-w in the 40-70 kDa range, with PD between 2.1 and 2.5; all were semicrystalline polymers with melting temperatures between 100 and 150 degrees C and T-g in the 50-80 degrees C range. The aromatic PURs were amorphous materials with molecular weights between 18 kDa and 25 kDa and T-g above 130 degrees C. Hydrogenolysis of the PUR made from hexamethylene diisocyanate and benzyl tartrate yielded PURs containing up to 40% of free carboxylic side-groups. The tartrate-derived PURs displayed enhanced sensitivity to hydrolysis compared with their unsubstituted 2,6-PUR homologs. The PURs bearing free carboxylic groups were unique in being degraded by water upon incubation under physiological conditions. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2391-2407, 2009