Influence of radiation sterilization on poly(ester urethanes) designed for medical applications

Preparation of scaffolds for tissue regeneration requires elucidation of chemical and physical processes induced by ionizing radiation during radiation sterilization of polymeric materials used for these purposes. Such treatment induces many unintended and desired reactions that lead either to degradation or cross-linking of macromolecules. It was found that in poly(ester urethane) the ester segments are responsible predominantly for radiation induced phenomena. Some radicals generated following irradiation were identified under cryogenic conditions. Upon exposure to sterilizing dose cross-linking was confirmed on the basis of rheological changes in melted polymers. The results obtained by EPR spectroscopy and DRS revealed a relatively high susceptibility of poly(ester urethanes) on oxidation.