The effect of high-energy electron beam irradiation on the physicochemical properties of PET material

Polyethylene terephthalate (PET) is a thermoplastic polyester used in the manufacture of containers and packaging. PET waste occupies one of the top positions in terms of volume among polymer waste. The radiation modification of PET is a promising method for regulating its operational and technological properties. It is assumed that irradiation of PET waste with an electron beam will facilitate its secondary processing. The aim of this work was to study the effect of the ionizing radiation on the PET physicochemical and physicomechanical properties. For this purpose, samples were irradiated by hig-energy electron beam with energy 10 MeV and dose range 0–600 kGy. The radiation-induced EPR of the signal was measured, and the dose dependence was estimated. As a result, it was found that irradiation with electrons leads to a decrease in the melting temperature and an increase in the melt fluidity and glass transition temperature of PET. The hardness and rigidity of the irradiated samples increase. The changes in properties are explained by the destruction of PET macromolecules, which proceeds with the formation of carboxyl and carbonyl groups. •The EPR spectrum showed a linear dependence of the accumulation of radicals with an increase in the absorbed dose in the range from 5 to 240.•At absorbed dose of 600 kGy, the glass transition temperature of PET increased by 24.4 °C (or 29.9%).•Melt fluidity index increased by 32.5% at absorbed dose of 100 kGy, and by 84.9% at 600 kGy.•The decrease in the melting point of PET samples become significant after irradiation with dose above 240 kGy.•Doses ˃100 kGy, the association processes of macromolecules predominate over destruction processes due to the newly formed polar end groups.