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Prooxidant activity of phenolic stabilizers in polyolefins during accelerated photooxidation
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SYSNO ASEP 0505869 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Prooxidant activity of phenolic stabilizers in polyolefins during accelerated photooxidation Author(s) Šlouf, Miroslav (UMCH-V) RID, ORCID
Michálková, Danuše (UMCH-V)
Gajdošová, Veronika (UMCH-V) RID, ORCID
Dybal, Jiří (UMCH-V) RID, ORCID
Pilař, Jan (UMCH-V) RID, ORCIDSource Title Polymer Degradation and Stability. - : Elsevier - ISSN 0141-3910
Roč. 166, August (2019), s. 307-324Number of pages 18 s. Language eng - English Country NL - Netherlands Keywords photooxidation of polyolefins ; accelerated weathering ; hindered amine stabilizers Subject RIV CF - Physical ; Theoretical Chemistry OECD category Physical chemistry R&D Projects LM2015064 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) NV15-31269A GA MZd - Ministry of Health (MZ) GA17-05007S GA ČR - Czech Science Foundation (CSF) LO1507 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Method of publishing Limited access Institutional support UMCH-V - RVO:61389013 UT WOS 000480377900031 EID SCOPUS 85067608745 DOI 10.1016/j.polymdegradstab.2019.06.013 Annotation Polymer plaques made of high density polyethylene (HDPE) and of two types of cycloolefin copolymer (COC) differing in glass transition temperature, were stabilized with 0.2 or 1.0 wt % of natural (α-tocopherol) or synthetic (Irganox®1010) phenolic stabilizer or hindered amine stabilizer (Tinuvin®770) and aged using accelerated weathering technique (WOM). The efficiency of the phenolic stabilizers was compared among themselves and with well-established Tinuvin®770. Concentration profiles of radicals generated inside polymer plaques during WOM exposure were determined by ESRI, profiles of oxidation products and crystallinity inside the HDPE plaques were determined by IR microspectroscopy, oxidation products in COC copolymers were identified using ATR, the changes of local mechanical properties of the polymer plaques were characterized using microindentation hardness testing, and their morphology was studied by light and/or scanning electron microscopy. All the techniques evidenced high stability of neat COC against photooxidation processes, whereas neat HDPE exhibited fast photooxidation of the surface layers. Tinuvin®770 was found to provide long term protection to both HDPE and COC against photodegradation. In contrast, the same polymers stabilized with the natural phenolic antioxidant α-tocopherol (the most active component of vitamin E) or synthetic phenolic antioxidant Irganox®1010 exhibited an increase in the surface oxidation in comparison with the neat polymers during WOM exposure, proving prooxidant activity of phenolic stabilizers during WOM exposure in all polymers studied. The prooxidant activity α-tocopherol was stronger in comparison with Irganox®1010. We conclude that neither of the two phenolic stabilizers was able to provide long term protection of the investigated polymers against photooxidation. Workplace Institute of Macromolecular Chemistry Contact Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358 Year of Publishing 2020 Electronic address https://www.sciencedirect.com/science/article/pii/S0141391019302162?via%3Dihub
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