Catalyst-Free Ring Opening Synthesis of Biodegradable Poly(ester-urethane)s Using Isosorbide Bio-Based Initiator

Polycaprolactones are obtained via ring opening polymerization of epsilon-caprolactone in catalyst-free condition. The polymerization is initiated in bulk, using isosorbide-based amino-alcohol as a biosourced initiator. The ratio of initiator to epsilon-caprolactone, as well as to temperature, is optimized in order to tune the hydroxyl number (Nr. OH) and the average molecular weight of the polymers. In addition, these biocompatible polyesters are used as soft-block to prepare thermoplastic poly(esterurethane)s elastomers via a simple one-pot catalyst-free polymerization. The successful synthesis of poly(esterurethane)s is confirmed by Fourier transform-infrared spectroscopy, and the thermal properties are studied by differential scanning calorimetry. These novel materials exhibit glass transition temperatures ranging from 7 to 38 degrees C. The biodegradability of these elastomers is evaluated by enzymatic degradation tests performed at rt in phosphate buffer solution (pH approximate to 7.4). The mass loss of polymer films is around 3% after 4 weeks. Scan electron as well as atomic force microscopies are used to show the degradation patterns.