Signori, F., Lips, P.A.M., Dijkstra, P.J., Feijen, J. and Chiellini, E
Macromolecular chemistry and physics 205, 1299-1308.
A series of poly(ether ester)s containing amide and carbamate groups as H-bonding units and 13-50 mol-% of poly(ethylene glycol) (PEG) segments were prepared by polycondensation in bulk using Ti(OBu)4 as a catalyst. The copolymers were obtained starting from PEG/1,4-butanediol mixtures and a synthetic monomer carrying H-bonding groups. These polymers were designed for biomedical applications, where material biodegradability is required. The influence of the nature of the H-bonding units, the length of the polymethylene spacer between the H-bonding groups and the PEG content on the thermal and solubility properties of the copolymers was investigated. Amide-containing copolymers were more thermally stable than those containing carbamate groups. The PEG content also slightly affected the polymer thermal stability. The DSC traces of all samples presented multiple transitions, whose shape and peak temperature were strongly dependent on the PEG content. Polymer hydrophilicity, surface free energy and equilibrium swelling in phosphate buffer solution (PBS) at 37 °C were mainly influenced by the PEG content, whereas the nature of the H-bonding groups had little effect.