Pro-oxidant activity of .alpha.-tocopherol during photooxidative degradation of polyolefins. ESRI and IR microspectroscopy studies

Pilař, Jan; Šlouf, Miroslav; Michálková, Danuše; Šloufová, I.; Vacková, Taťana; Dybal, Jiří

doi:https://dx.doi.org/10.1016/j.polymdegradstab.2017.02.008

Number of the records: 1

Pro-oxidant activity of .alpha.-tocopherol during photooxidative degradation of polyolefins. ESRI and IR microspectroscopy studies

1.

SYSNO ASEP	0472352
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Pro-oxidant activity of .alpha.-tocopherol during photooxidative degradation of polyolefins. ESRI and IR microspectroscopy studies
Author(s)	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, ORCID}
Source Title	Polymer Degradation and Stability. - : Elsevier - ISSN 0141-3910 Roč. 138, April (2017), s. 55-71
Number of pages	17 s.
Language	eng - English
Country	NL - Netherlands
Keywords	polymer photooxidation ; stabilization ; HAS
Subject RIV	CD - Macromolecular Chemistry
OECD category	Polymer science
R&D Projects	NV15-31269A GA MZd - Ministry of Health (MZ)
	LM2015064 GA MŠMT - Ministry of Education, Youth and Sports (MEYS)
	GA14-17921S GA ČR - Czech Science Foundation (CSF)
	LO1507 GA MŠMT - Ministry of Education, Youth and Sports (MEYS)
Institutional support	UMCH-V - RVO:61389013
UT WOS	000400222500007
EID SCOPUS	85014733947
DOI	10.1016/j.polymdegradstab.2017.02.008
Annotation	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.
Workplace	Institute of Macromolecular Chemistry
Contact	Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358
Year of Publishing	2018

Number of the records: 1