Migration of Irgafos168 and Its Degradation Products from Poly(butyleneadipate-co-terephthalate)/Polylactic Acid Composite Materials under Three Working Conditions

The migration of the antioxidant Irgafos168 and its degradation products from poly(butyleneadipate-co-terephthalate)/polylactic acid (PBAT/PLA) composite films into the fatty food simulant isooctane under different working conditions (ultraviolet (UV), high humidity and salt atmosphere) was studied by gas chromatography-mass spectroscopy (GC-MS), and the aging degree of composite films under each condition was investigated in terms of their mechanical properties and infrared characteristics. The results showed that the degradation of PBAT/PLA composite films was greatly affected by UV and high humidity conditions. After two days of UV exposure, 60 days of high humidity exposure and 40 days of salt spray exposure, the tensile strength of the composite films decreased by 61.1%, 41.6% and 35.9% to 10, 15 and 17 MPa, respectively, and the elongation at break decreased by 93.5%, 34.1% and 21.5%, respectively. The antioxidant’s concentration had no significant effect on the properties of the composite films (P > 0.05). The migration of Irgafos168 and its degradation products was positively correlated with their initial levels in the composite films. The migration of Irgafos168 from the untreated composite film was the highest (85.39 mg/kg). The content of Irgafos168’s degradation products in the composite films increased with aging, the major one being tri(2,4-di-tert-butylphenyl) phosphate, which was produced in the largest amounts under UV conditions, and the migration of tri(2,4-di-tert-butylphenyl) phosphate was 3.04-99.50 mg/kg. The migration of the substances could be affected by temperature, their initial contents and the aging degree of the composite films.