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 longterm 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.

This work investigates the potential application of e-beam radiation for sterilization of food packaging made of commercial polyester blend of poly(butylene adipate-co-terephthalate) and polylactide known under the trade name Ecovio 23B1. Ecovio film was irradiated at doses of 5, 13, and 26 kGy and the effect of sterilization on the microorganism inactivation ability was performed. The influence of radiation doses on structural and packaging properties such as tensile strength, barrier, and migration properties was also studied. 1 H NMR and FTIR analysis revealed no significant changes in the polymer structure, however, the molar mass of irradiated samples decreased with increasing radiation dose. This result indicated the occurrence of degradation process during radiation, which was confirmed by the thermal analysis and accelerated enzymatic degradation. The packaging properties did not changed significantly and the overall migration for 10% ethanol, isooctane, and MPPO was below the limit for all of the studied samples.

This work investigates the potential application of various sterilization methods for microorganism inactivation on the thermoplastic starch blend surface. The influence of the e-beam and UV radiation, ethanol, isopropanol and microwave autoclave on structural and packaging properties were studied. All the applied methods were successful in the inactivation of yeast and molds, however only the e-beam radiation was able to remove the bacterial microflora. The FTIR analysis revealed no significant changes in the polymer structure, nevertheless, a deterioration of the mechanical properties of the blend was observed. The least invasive method was the UV radiation which did not affect the mechanical parameters and additionally improved the barrier properties of the tested material. Moreover, it was proved that during the e-beam radiation the chain scission and cross-linking occurred. The non-irradiated and irradiated samples were subjected to the enzymatic degradation studies performed in the presence of amylase. The results indicated that irradiation accelerated the decomposition of material, which was confirmed by the measurements of weight loss, and mass of glucose and starch released to the solution in the course of biodegradation, as well as the FTIR and thermal analysis.

The effect of exposure of polylactide (PLA) and poly(trimethylene carbonate) (PTMC) statistical copolymers to ionizing radiation was studied by means of EPR spectroscopy. In addition, the influence of radiation‐induced processes on thermal properties, miscibility of the components, weight average molecular weight (Mw) and number average molecular weight (Mn) were investigated for doses in the range of 0–200 kGy. In copolymers containing PLA and PTMC components in a ratio of 30:70 and 70:30 PLA radicals identified in the homopolymer under cryogenic conditions were dominant. This showed that PTMC radical centers either recombine or are transferred to PLA along the macromolecules. The results obtained for the non‐irradiated and irradiated samples showed that the glass transition values measured by differential scanning calorimetry and calculated using the Fox equation were similar and indicated compatibility between the constituents of the tested copolymers and their miscibility. Mw and Mn changes measured by gel permeation chromatography were used to determine the radiation yield of scission G(S) and cross‐linking G(X). In the case of PLA and PLA‐rich copolymers, the difference between G(S) and G(X) with increasing dose increased, thus the chain scission predominated over cross‐linking. For PTMC rich copolymer, the effect was opposite.