Effects of Electron Beam Sterilization on Polytetrafluoroethylene: Design of Experiments Study.

Polytetrafluoroethylene (PTFE) is a common polymer used in medical devices due to its exceptional properties (e.g., biocompatibility, inertness, chemical stability, low coefficient of friction). However, as a result of molecular weight reduction caused by the process of chain scission, it is known to be susceptible to radiation exposure and can rapidly lose strength and integrity. In this design of experiments study, the goal was to determine whether an operating window of conditions exist for electron beam (E-beam) radiation sterilization in which the degradation of PTFE is acceptably low. PTFE was tested for yield stress after exposure to radiation under different parameters (total dose [15-60 kGy], packaging atmosphere [air/nitrogen], and poststerilization accelerated aging [real-time equivalent of 1 and 3 years]). The results showed that total dose and packaging atmosphere were significant factors and indicated that the use of modified atmosphere packaging (vacuum sealing with nitrogen gas purge) can be a useful approach in increasing the stability of PTFE toward E-beam sterilization.