epsilon-Decalactone (epsilon-DL), whose homopolymer is completely amorphous owing to the racemic stereochemistry of its butyl side chain, was copolymerized with omega-pentadecalactone (omega-PDL) in order to reduce the high crystallization capability of the latter. NMR characterization showed that the poly(omega-PDL-co-epsilon-DL), with omega-PDL molar contents ranging from 30 to 78%, presented a blocky chain microstructure (randomness character R < 0.49). omega-PDL homopolymer (PPDL), with a Tm at 104 degrees C and a T-g at = -36 degrees C, exhibited a degree of crystallinity of 54% and the incorporation of epsilon-DL decreased its crystalline fraction to 13e38% and the T-g to around -50 degrees C. As a result, these copolymers displayed high elongation at break values and lower stiffness than PPDL (with secant modulus of 7e156 MPa) while their mechanical properties remained constant at 37 degrees C. The poly(omega-PDL-co-epsilon-DL), with a melting enthalpy in the range of between 36 and 106 Jg(-1), presented a melting temperature higher than 69 degrees C and showed great thermal stability, degrading at temperatures higher than 400 degrees C. However, in vitro degradation studies during 182 days demonstrated that, despite their increased amorphous character, these materials were very resistant to hydrolysis due to the steric effect of the epsilon-DL units, and can virtually be considered as nonbiodegradable polymers. (C) 2015 Elsevier Ltd. All rights reserved.