Authors
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Šlouf, M.; Gajdošová, V.; Šloufová, I.; Lukešová, M.; Michálková, D.; Müller, M. T.; Pilař, J.
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Title
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Degradation processes in polyolefins with phenolic stabilizers subjected to ionizing or non-ionizing radiation
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Date
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27.02.2024
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Number
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0
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Abstract
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We investigated degradation processes in polymer plaques made of polyolefin (HDPE or UHMWPE or COC) prepared by melt-mixing with or without phenolic stabilizer (natural α-tocopherol or synthetic Irganox®1010) and spin trapping agent (TTBNB; 2,4,6-Tri‑tert-butylnitrosobenzene). The degradation was initiated either by low-energy, non-ionizing radiation (wavelengths corresponding to terrestrial range of solar UV radiation) or high-energy, ionizing radiation (electrons accelerated at 1.5 MeV). The motivation for the study was our recent finding that some phenolic stabilizers exhibited a surprising pro-oxidant activity in polyolefins subjected to non-ionizing radiation. Consequently, we asked if the phenolic stabilizers in polyolefins behave in the same way during long-term, low-energy, non-ionizing UV irradiation and after short-term, high-energy, ionizing e-beam irradiation. All samples were characterized thoroughly by means of electron spin resonance (ESR; the information about radiation-induced radicals), infrared microspectroscopy (IR; the detection of oxidation products and structural changes), instrumented microindentation (MHI; local mechanical properties) and light and electron microscopy (LM and SEM; surface morphology). The results proved that (i) the degradation processes in polyolefins subjected to non-ionizing or ionizing radiation were different, (ii) the phenolic stabilizers exhibited mostly their expected antioxidant activity, while pro-oxidant activity was detected only for specific conditions and/or systems subjected to non-ionizing radiation, and (iii) the selected spin trapping agent, TTBNB, was stable enough to survive standard sample preparation by melt-mixing and catch short-living unstable radicals.
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Publisher
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Elsevier
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Wikidata
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Citation
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Polymer Degradation and Stability 222 (2024) 110708
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DOI
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https://doi.org/10.1016/j.polymdegradstab.2024.110708
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Tags
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