Influence of electron beam irradiation on physicochemical properties of poly(trimethylene carbonate)

Electron beam (EB) irradiation of poly(trimethylene carbonate) (PTMC), an amorphous, biodegradable polymer used in the field of biomaterials, results in predominant cross-linking and finally in the formation of gel fraction, thus enabling modification of physicochemical properties of this material without significant changes in its chemical structure. PTMC films (Mw: 167-553 kg mol−1) were irradiated with different doses using an electron accelerator. Irradiation with a standard sterilization dose of 25 kGy caused neither significant changes in the chemical composition of the polymer nor significant deterioration of its mechanical properties. Changes in viscosity-, number-, weight-, and z-average molecular weights of PTMC for doses lower than the gelation dose (Dg) as well as gel-sol analysis and swelling tests for doses above Dg indicate domination of cross-linking over degradation. EB irradiation can be considered as an effective tool for increasing the average molecular weight of PTMC and sterilization of PTMC-based biomaterials.