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Evaluation and Modeling of Polylactide Photodegradation under Ultraviolet Irradiation: Bio-Based Polyester Photolysis Mechanism.

Sergey M LomakinYurii MikheevSergey UsachevSvetlana RogovinaLubov ZhorinaEvgeniya PerepelitsinaIrina LevinaOlga KuznetsovaNatalia ShilkinaAlexey Leonidovich IordanskiiAlexander Berlin
Published in: Polymers (2024)
In our study, we investigated the accelerated aging process of PLA under 253.7 nm UV-C irradiation with the use of the GPC, NMR, FTIR, and DSC methods and formal kinetic analysis. The results of GPC and DSC indicated a significant degree of destructive changes in the PLA macromolecules, while spectroscopic methods NMR and FTIR showed maintenance of the PLA main structural elements even after a long time of UV exposure. In addition to that, the GPC method displayed the formation of a high molecular weight fraction starting from 24 h of irradiation, and an increase in its content after 144 h of irradiation. It has been shown for the first time that a distinctive feature of prolonged UV exposure is the occurrence of intra- and intermolecular radical recombination reactions, leading to the formation of a high molecular weight fraction of PLA decomposition products. This causes the observed slowdown of the photolysis process. It was concluded that photolysis of PLA is a complex physicochemical process, the mechanism of which depends on morphological changes in the solid phase of the polymer under UV radiation.
Keyphrases
  • magnetic resonance
  • radiation induced
  • risk assessment
  • dna damage
  • machine learning
  • aqueous solution
  • solid state
  • molecular docking
  • dna repair
  • radiation therapy
  • deep learning
  • light emitting
  • neural network