Investigating dose rate effects and reactive species formation in irradiated multilayer films – part 1 EVA/EVOH/EVA

This study investigates the effects of gamma rays, X-rays, and electron beams on ethylene vinyl acetate (EVA) multilayer films, commonly used in biotechnological applications. Electron spin resonance (ESR) analysis showed that irradiation generates unstable hydroxyalkyl radicals, quantifiable one day post-exposure, with concentrations decreasing within nine days, and with similar kinetics observed across all three irradiation technologies. The research focuses on dose rate impacts, which significantly influence polymer properties. Reactive species like hydrogen peroxide and hydroxyl radicals, generated during irradiation, can affect protein function through methionine oxidation. Advanced analytical techniques reveal that the dose rate significantly impacted the levels of reactive species, impacting the film's structural integrity and chemical stability comparably. Gamma irradiation generates more oxidative species. The study concludes that dose rate is crucial in methionine sulfoxide generation, with longer exposure leading to increased concentrations, particularly in gamma irradiation. These findings underscore the importance of considering dose rate and irradiation technology to optimize the stability and performance of multilayer films.