Preparation and characterization of aliphatic/aromatic copolyesters based on bisphenol-A terephthalate, hexylene terephthalate and lactide mioties

To obtain higher molecular weight processable polyesters which are of potential interest for tissue engineering, a series of biodegradable aliphatic/aromatic copolyesters, poly(4,4'-isopropylidenediphenyl terephthalate)-co-poly(hexylene terephthalate)-co-polylactide (PBHTL), were synthesized via direct polycondensation from terephthaloyl dichloride, bisphenol-A, 1,6-hexanediol, and oligolactide. The resulting copolyesters, PBHTL, were characterized by proton nuclear magnetic resonance (H-1 NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetry (TG) and wide-angle X-ray scattering (WAXS), and their glass transition temperature (T-g), and thermal decomposition temperature (T-d) were obtained. The PBHTL shows two-step thermal decomposition, which is corresponding to segment of 4,4'-isopropylidenedil)henyl terephthalate (BAT) and segments of hexylene tereplithalate (HT) and lactide (LA), respectively. Due to the incorporation of flexible aliphatic unit into the main chains of copolyesters, PBHTL has lower T-g, and shows enhanced hydrolytic degradability under a physiological conditions with increasing lactide and hexylene moieties. Initial experiments indicated excellent biocompatibility based on cell seeding experiments and microscopic evidence. (c) 2007 Elsevier Ltd. All rights reserved.