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Pro-oxidant activity of .alpha.-tocopherol during photooxidative degradation of polyolefins. ESRI and IR microspectroscopy studies
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SYSNO ASEP 0472352 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Pro-oxidant activity of .alpha.-tocopherol during photooxidative degradation of polyolefins. ESRI and IR microspectroscopy studies Tvůrce(i) Pilař, Jan (UMCH-V) RID, ORCID
Šlouf, Miroslav (UMCH-V) RID, ORCID
Michálková, Danuše (UMCH-V)
Šloufová, I. (CZ)
Vacková, Taťana (UMCH-V) RID
Dybal, Jiří (UMCH-V) RID, ORCIDZdroj.dok. Polymer Degradation and Stability. - : Elsevier - ISSN 0141-3910
Roč. 138, April (2017), s. 55-71Poč.str. 17 s. Jazyk dok. eng - angličtina Země vyd. NL - Nizozemsko Klíč. slova polymer photooxidation ; stabilization ; HAS Vědní obor RIV CD - Makromolekulární chemie Obor OECD Polymer science CEP NV15-31269A GA MZd - Ministerstvo zdravotnictví LM2015064 GA MŠMT - Ministerstvo školství, mládeže a tělovýchovy GA14-17921S GA ČR - Grantová agentura ČR LO1507 GA MŠMT - Ministerstvo školství, mládeže a tělovýchovy Institucionální podpora UMCH-V - RVO:61389013 UT WOS 000400222500007 EID SCOPUS 85014733947 DOI 10.1016/j.polymdegradstab.2017.02.008 Anotace Photooxidation processes inside high-density polyethylene (HDPE) and cyclic olefin copolymer (COC) poly(ethylene-co-norbornene), both stabilized with biological antioxidant alpha-tocopherol (alpha-T-OH), has been investigated. Plaques made of the polymers stabilized with alpha-T-OH were subjected to long-term accelerated weathering in a Weather-Ometer (WOM). Concentration profiles of radicals generated in the plaques in dependence on WOM exposure time were determined by electron spin resonance imaging (ESRI). Concentration profiles of oxidation products and stabilizer, together with local crystallinity profiles inside the polymer plaques were determined by infrared (IR) microspectroscopy. The ESRI and IR profiles, supplemented by light microscopy (LM) and microindentation hardness measurements (MH), revealed the heterogeneity of the oxidation process and, surprisingly, the pro-oxidative activity of alpha-T-OH. Increasing concentration of products of polymer oxidation was found in the surface layers of the plaques stabilized with alpha-T-OH since the beginning of WOM treatment unlike the same control experiments with polymer plaques stabilized with HAS Tinuvin® 770, where no oxidation products were observed after the same treatment before HAS depletion. We have confirmed that alpha-T-OH exhibits antioxidant activity during thermooxidation but it acts as a pro-oxidant agent during photooxidation. Pracoviště Ústav makromolekulární chemie Kontakt Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358 Rok sběru 2018
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