The goal of this research is to synthesize biodegradable polymers that would have nitroxyl radical biological functions. Linear aliphatic polyesters were chosen as the starting materials. The hydroxyl-terminated polylactide/epsilon -caprolactones (PBLC-OHs) were first synthesized by melt ring-opening copolymerization in the presence of benzyl alcohol and stannous octoate. PBLC-OHs were used as the precursor for the synthesis of double bond-functionalized polylactide/epsilon -caprolactones (PBLC-Mas) by reacting the hydroxyl end groups of PBLC-OH with maleic anhydride in melt at 130 degreesC. Acrylic acid/lactide/epsilon -caprolactone g-raft copolymers (PBLCAs) were then successfully carried out by the radical copolymerization of acrylic acid and PBLC-Ma initiated by azobisisobutyronitrile. Finally, nitroxyl radicals [4-amino-2,2,6,6-tetramethylpiperidine-1-oxy (TAM)] were incorporated into the carboxylic acid sites of the acrylic acid/lactide/epsilon -caprolactone copolymer (TAM-PBLCA) by reacting TAM with PBLCA in the presence of NX-carbonyl diimidazole. A high content of TAM was incorporated into the PBLCA copolymer. The polymers synthesized were characterized by H-1 and C-13 NMR. Fourier transform infrared spectroscopy, and electron paramagnetic resonance spectra.