Synthesis, characterization, and hydrolytic degradation of biodegradable poly(ether ester)-urethane copolymers based on ε-caprolactone and poly(ethylene glycol)

In this article, a new kind of biodegradable poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone)-based polyurethane (PCEC-U) copolymers were successfully synthesized by melt-polycondensation method from ε-caprolactone (ε-CL), poly(ethylene glycol) (PEG), 1,4-butanediol (BD), and isophorone diisocyanate (IPDI). The obtained copolymers were characterized by ¹H-nuclear magnetic resonance (¹H-NMR), FTIR, and gel permeation chromatography (GPC). Thermal properties of PCEC-U copolymers were studied by DSC and TGA/DTG under nitrogen atmosphere. Water absorption and hydrolytic degradation behavior of these copolymers were also investigated. Hydrolytic degradation behavior was studied by weight loss method. ¹H-NMR and GPC were also used to characterize the hydrolytic degradation behavior of PCEC-U copolymers. The molecular weight of PCL block and PEG block in soft segment and the content of hard segment strongly affected the water absorption and hydrolytic degradation behavior of PCEC-U copolymers.