Physicochemical characterization and degradation characteristics of segmented polyurethaneureas prepared from aliphatic diisocyanates

The two kinds of segmented polyurethaneureas (SPUU) were synthesized via standard two step prepolymer method using aliphatic diisocyanates, biodegradable polyester diol, poly (-ε-caprolactone diol). DSC, WAXD, dynamic viscoelastic measurements, and tensile test were carried out. DSC measurement revealed that the relative ratio of PCL and BDA segments in these SPUU changed the crystallinity of PCL segment. Furthermore, the LDI based SPUU with 71% PCL segment (PCL(1250)(71)LDI-BDA) and BDI based SPUU with 77% PCL segment (PCL(1250)(77)BDI-BDA) showed good elastic properties. This behavior can be originated from the partial phase mixing of LDI and PCL for PCL(1250)(71)LDI-BDA and the formation of crystalline hard segment for PCL(1250)(77)BDI-BDA. Finally, degradability of LDI and BDI-based SPUU were evaluated by the change in weight with time exposing the polymers to tris buffered saline solution at 310 K (pH=7.6). The weight loss of both SPUU was about 10% after 70 days.