Review of the effects of irradiation treatments on poly(ethylene terephthalate)

Ionizing radiation can initiate a variety of chemical reactions under any circumstances without applying catalysts in polymer materials. It can be applied intentionally to modify polymeric materials by inducing chemical reactions like chain scission, crosslinking, and structural transformation. This review presents the effect of various irradiation processes on the chemical structure, physical and mechanical properties of poly(ethylene terephthalate) (PET) including electron beam, gamma, ultraviolet, ion beam, and laser irradiation. Generally, the PET structure is susceptible to modification via chain scission reactions and eventually the cleavage of ester and methylene groups. New chemical bonds including polar functional groups like hydroxyl and carboxylic acid groups as well as conjugated bonds can also form. In addition, the PET mesostructure can transform under irradiation resulting in different crystalline arrangements. Therefore, irradiation processing through the regulation of absorbed dosage can modify PET structure to provide different optical, physical, and mechanical properties for various applications.