Improvement of biocompatibility and biodegradability of poly(ethylene succinate) by incorporation of poly(ethylene glycol) segments

Poly(ethylene glycol) (PEG) segments were incorporated into poly(ethylene succinate) (PES) by chain-extension reaction of PEG with PES using 1,6-hexamethylene diisocyanate as a chain-extender, forming a poly(ester ether urethane) (PEEU). The chemical structures and molecular weights of the PEEUs were determined by 1H NMR and GPC, respectively. The composition dependence of thermal transitions, crystallization, hydrophilicity, in vitro biocompatibility, in vitro biodegradation and tensile properties of the PEEUs were systematically investigated. The glass transition temperature and degree of crystallinity of PEEU decreased with increase of PEG content. The hydrophilicity increased with PEG content as proved by the decreased water contact angle and increased water absorption. The results of cell culturing suggested that the in vitro biocompatibility increased with PEG content. Hydrolytic degradation demonstrated that degradation rate of PEEU increased with PEG content, which was caused by the increased hydrophilicity and decreased degree of crystallinity with increase of PEG content. The tensile results proved that the tensile strength and modulus decreased while elongation at break increased with PEG content.