Influence of e-beam irradiation on the dynamic creep and fatigue properties of poly(aliphatic/aromatic-ester) copolymers for biomedical applications

Biomaterials must meet special medical prerequisites like biocompatibility and resistance to degradation and fracture, especially under cyclic loading. Promising candidates are poly(aliphatic/aromatic-ester) (PED) multiblock copolymers, which belong to the class of thermoplastic elastomers (TPEs), characterized by a physical network of semi-crystalline hard segments. Here we focus on the dynamic creep and fatigue performance of these TPEs and compare their behaviour with commercial benchmark materials. The PEDs were e-beam cured, to enhance their fatigue behaviour by the formation of an additional network structure. All materials were evaluated using quasi-static tensile tests and dynamic hysteresis measurements. Their mechanical properties were related to the network structure. E-beam irradiation increased the tensile strength and decreased the dynamic creep rate of PEDs. This effect can be explained by the formation of chemical cross-links, which are located in the hard phase segments. In conclusion, these novel biomaterials are a comparable alternative to their commercial counterparts like silicones and thermoplastic polyurethanes.