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Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers

Ultra-high molar mass polyethylene (UHMMPE) is commonly used for ballistic-resistant body armor applications due to the superior strength of the fibers fabricated from this material combined with its low density. However, polymeric materials are susceptible to thermally induced degradation during st...

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Autores principales: Tsinas, Zois, Orski, Sara V., Bentley, Viviana R. C., Gonzalez Lopez, Lorelis, Al-Sheikhly, Mohamad, Forster, Amanda L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9002805/
https://www.ncbi.nlm.nih.gov/pubmed/35406198
http://dx.doi.org/10.3390/polym14071324
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author Tsinas, Zois
Orski, Sara V.
Bentley, Viviana R. C.
Gonzalez Lopez, Lorelis
Al-Sheikhly, Mohamad
Forster, Amanda L.
author_facet Tsinas, Zois
Orski, Sara V.
Bentley, Viviana R. C.
Gonzalez Lopez, Lorelis
Al-Sheikhly, Mohamad
Forster, Amanda L.
author_sort Tsinas, Zois
collection PubMed
description Ultra-high molar mass polyethylene (UHMMPE) is commonly used for ballistic-resistant body armor applications due to the superior strength of the fibers fabricated from this material combined with its low density. However, polymeric materials are susceptible to thermally induced degradation during storage and use, which can reduce the high strength of these fibers, and, thus, negatively impact their ballistic resistance. The objective of this work is to advance the field of lightweight and soft UHMMPE inserts used in various types of ballistic resistant-body armor via elucidating the mechanisms of chemical degradation and evaluating this chemical degradation, as well as the corresponding physical changes, of the UHMMPE fibers upon thermal aging. This is the first comprehensive study on thermally aged UHMMPE fibers that measures their decrease in the average molar mass via high-temperature size exclusion chromatography (HT-SEC) analysis. The decrease in the molar mass was further supported by the presence of carbon-centered free radicals in the polyethylene that was detected using electron paramagnetic resonance (EPR) spectroscopy. These carbon-centered radicals result from a cascade of thermo-oxidative reactions that ultimately induce C–C ruptures along the backbone of the polymer. Changes in the crystalline morphology of the UHMMPE fibers were also observed through wide-angle X-ray diffraction (WAXS), showing an increase in the amorphous regions, which promotes oxygen diffusion into the material, specifically through these areas. This increase in the amorphous fraction of the highly oriented polyethylene fibers has a synergistic effect with the thermo-oxidative degradation processes and contributes significantly to the decrease in their molar mass.
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spelling pubmed-90028052022-04-13 Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers Tsinas, Zois Orski, Sara V. Bentley, Viviana R. C. Gonzalez Lopez, Lorelis Al-Sheikhly, Mohamad Forster, Amanda L. Polymers (Basel) Article Ultra-high molar mass polyethylene (UHMMPE) is commonly used for ballistic-resistant body armor applications due to the superior strength of the fibers fabricated from this material combined with its low density. However, polymeric materials are susceptible to thermally induced degradation during storage and use, which can reduce the high strength of these fibers, and, thus, negatively impact their ballistic resistance. The objective of this work is to advance the field of lightweight and soft UHMMPE inserts used in various types of ballistic resistant-body armor via elucidating the mechanisms of chemical degradation and evaluating this chemical degradation, as well as the corresponding physical changes, of the UHMMPE fibers upon thermal aging. This is the first comprehensive study on thermally aged UHMMPE fibers that measures their decrease in the average molar mass via high-temperature size exclusion chromatography (HT-SEC) analysis. The decrease in the molar mass was further supported by the presence of carbon-centered free radicals in the polyethylene that was detected using electron paramagnetic resonance (EPR) spectroscopy. These carbon-centered radicals result from a cascade of thermo-oxidative reactions that ultimately induce C–C ruptures along the backbone of the polymer. Changes in the crystalline morphology of the UHMMPE fibers were also observed through wide-angle X-ray diffraction (WAXS), showing an increase in the amorphous regions, which promotes oxygen diffusion into the material, specifically through these areas. This increase in the amorphous fraction of the highly oriented polyethylene fibers has a synergistic effect with the thermo-oxidative degradation processes and contributes significantly to the decrease in their molar mass. MDPI 2022-03-24 /pmc/articles/PMC9002805/ /pubmed/35406198 http://dx.doi.org/10.3390/polym14071324 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Tsinas, Zois
Orski, Sara V.
Bentley, Viviana R. C.
Gonzalez Lopez, Lorelis
Al-Sheikhly, Mohamad
Forster, Amanda L.
Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers
title Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers
title_full Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers
title_fullStr Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers
title_full_unstemmed Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers
title_short Effects of Thermal Aging on Molar Mass of Ultra-High Molar Mass Polyethylene Fibers
title_sort effects of thermal aging on molar mass of ultra-high molar mass polyethylene fibers
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9002805/
https://www.ncbi.nlm.nih.gov/pubmed/35406198
http://dx.doi.org/10.3390/polym14071324
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