Design, Synthesis and Characterization of Novel Biodegradable Poly(urethane-urea) for Biomedical Applications

A series of novel biodegradable poly(urethane-urea) were designed and synthesized based on poly(D,L-lactic acid)diol, 1,6-hexamethylene diisocyanate and piperazine. Their structure and mechanical properties were characterized by fourier transform infrared spectroscopy, nuclear magnetic resonance and dynamic mechanical analysis. These results revealed that the successful introduction of the piperazine into the backbone of the biodegradable poly(urethane-urea) could make them have excellent mechanical properties. Increasing the hard segments of biodegradable poly(urethane-urea), the T-g and storage modulus of biodegradable poly(urethane-urea) increased from 29.35 to 55.63 degrees C and from 2523 to 3295 Mpa, respectively. Moreover, in vitro degradation tests confirmed that piperazine as the chain extender would improve the biodegradable stability of biodegradable poly(urethane-urea) and regulate its degradation rate.