In vitro degradation of poly(lactide-co-p-dioxanone)-based shape memory poly(urethane-urea)

The degradation of poly(lactide-co-p-dioxanone)-based shape memory poly(urethane-urea) (SMPU) in vitro was investigated by observing the changes of the pH value of incubation media, weight loss rate, molecular weight and scanning electron microscopy (SEM) during degradation duration of 12 weeks. Moreover, 1H NMR was used to precisely study the degradation position by calculating the change of characteristic peaks value. The results revealed that the introduction of p-dioxanone (PDO) and -NH-(CO)- and -HN-(CO)-NH- would increase the hydrophilicity of polymer, so the degradation of SMPUs is higher than PDLLA control in the initial time, however, the degradation rate decreased in the anaphase of degradation, which can be attributed to the alkalic -NH2 from the NH2 and -NH-(CO), -NH-(CO)-NH-.