Radiation degradation and stability of PBAT: copolymer of aromatic and aliphatic esters

Effect of the exposure of poly(butylene adipate-co-terephthalate) (PBAT) to ionizing radiation was studied by means of EPR and diffuse reflection spectroscopy, GC, and gel permeation chromatography. In addition, the influence of radiation-induced processes on mechanical and rheological properties for the doses in the range 0-200 kGy was investigated. The macroscopic consequences of PBAT irradiation included: crosslinking, chain cleavage, and oxidation, which led to the significant modification of physicochemical features. The crosslinking process occurred even under cryogenic conditions and was confirmed by reduction in melt flow index (MFI), increase in viscosity, and weight-average molecular weight with increasing dose. Material degradation during long-term storage was accompanied by deterioration of mechanical properties, increase in MFI, and viscosity reduction. Oxidation of the copolyester had a chain character and increased over time, especially in the case of irradiated PBAT. Despite the presence of aromatic rings dissipating energy, the material is susceptible to ionizing radiation. The regions containing terephthalates are involved in the aging processes; the appropriate mechanisms have been proposed. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46682.