The Effect of Molecular Weight on the Physical Properties and In Vitro Enzymatic Degradation Behavior of Poly(ε-caprolactone)

The poly(ε-caprolactone)s (PCLs) with different molecular weights were synthesized. The molecular weight played an important role in the physical properties of PCL. The results of thermal properties showed that as the molecular weight increased from 90 kDa to 210 kDa, the Tg and Td increased from –64.5 to –61.7 °C and from 292.4 to 354.0 °C, respectively, while the crystallinity decreased from 39.92 to 31.82% that caused a decrease in the mechanical properties of PCL. The results of the in vitro enzymatic degradation showed that PCL degraded in lipase via surface erosion, and the lipase could act as a surfactant to diffuse the degradation products into degradation medium. The effect of the molecular weight on the degradation rate of PCL was also investigated, and a lower degradation rate was seen for the high molecular weight PCL. The mass loss decreased from 73.19 to 65.06% due to the restricted movement of the PCL polymer segment, as the molecular weight increased from 90 kDa to 210 kDa. The results indicate that PCL is a promising candidate for bone defect reparation due to its tunable properties.