  Thermo plastic polyurethane (TPU) provides excellent bio-compatibility,
flexibility and good irradiation resistance; however, extremely high
irradiation doses can alter the structure and function of macromolecules,
resulting in oxidation, chain scission and cross-linking. In this study, the
effects of e-beam irradiation on the medical grade thermo plastic polyurethane
were studied. The changes in the chain length and their distribution as well as
the changes in molecular structure were studied. The GPC (Gel Permeation
Chromatography) results show that the oxidative decomposition is followed by a
decrease in molecular mass together with an increase in polydispersity. This
indicates a very inhomogeneous degradation, which is a consequence of the
specific course and of the intensity of oxidative degradation. This was
confirmed by means of mechanical property measurements. Overall, this study
demonstrated that the medical grade TPU was affected by radiation exposure,
particularly at high irradiation doses.
