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

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F17%3A00472352" target="_blank" >RIV/61389013:_____/17:00472352 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216208:11310/17:10368329

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.polymdegradstab.2017.02.008" target="_blank" >http://dx.doi.org/10.1016/j.polymdegradstab.2017.02.008</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.polymdegradstab.2017.02.008" target="_blank" >10.1016/j.polymdegradstab.2017.02.008</a>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Polymer Degradation and Stability

ISSN

0141-3910

e-ISSN

—

Svazek periodika

138

Číslo periodika v rámci svazku

April

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

17

Strana od-do

55-71

Kód UT WoS článku

000400222500007

EID výsledku v databázi Scopus

2-s2.0-85014733947