Radical detection and electron-spin resonance (ESR) monitoring in polymer materials irradiated with gamma and X-rays: Polyethylene and polypropylene

When ionizing radiations interact with polymers, free radicals are generated and are known to be the initiating species for the modification in materials. Monitoring and identifying free radicals after irradiation allow assessing the impact of X-rays and gamma rays on materials. A comparative study has been performed on materials made from polypropylene and polyethylene after irradiation by the two irradiation technologies. Electron spin resonance (ESR) signal has been monitored up to 380 days when signal was still present. ESR signals, concentration profiles, and kinetics were observed after X-rays and gamma rays.