Polypropylene is a widely used material for medicaldisposables and food packing where sterilization isvery important. The protection e•ect o•ered by aro-matic additives has been observed. However, the rela-tive contribution of charge and energy transferprocesses has not been estimated up to now.A pulse radiolysis study of isotactic polypropylene(PP) film has been carried out with the main aim of in-vestigating ionic and excited species generated in pureand doped PP over a wide temperature range from ca30 K up to 295 K. Full experimental and other detailscan be found elsewhere (Mayer et al., 1998).In PP, electron (6–8 MeV) pulse irradiation gener-ates electron-positive hole pairs. The electron can bestabilized in the undoped system as a trapped electron,e