The radiosterilization of plastic packaging theoretically induces two types of chemical modifications, namely reticulation and cleavage, that depend not only on the chemical structure of the polymer, but also on the kind and dose of radiation. This article proposes a methodology for studying plasticized polyvinylchloride (PVC) behavior submitted to beta radiation. Analytical techniques such as thermogravimetric analysis (TGA) and size exclusion chromatography (SEC) coupled with a light scattering detector were used in this study. SEC has informed us directly on the modifications (reticulation, scission) that intervened after a radiotreatment; TGA allowed us to highlight polymer structural changes. In addition, FTIR was employed to demonstrate an intermolecular dehydrochlorination following the radiotreatment. The results of these investigations permitted us to demonstrate both a reticulation and a scission phenomena within the PVC polymer.