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On the Mechanisms of the Effects of Ionizing Radiation on Diblock and Random Copolymers of Poly(Lactic Acid) and Poly(Trimethylene Carbonate)
This article demonstrates that ionizing radiation induces simultaneous crosslinking and scission in poly(trimethylene carbonate-co-d-lactide) diblock and random copolymers. Copolymer films were electron-beam (EB) irradiated up to 300 kGy under anaerobic conditions and subsequently examined by evalua...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404164/ https://www.ncbi.nlm.nih.gov/pubmed/30966706 http://dx.doi.org/10.3390/polym10060672 |
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author | Adamus-Wlodarczyk, Agnieszka Wach, Radoslaw A. Ulanski, Piotr Rosiak, Janusz M. Socka, Marta Tsinas, Zois Al-Sheikhly, Mohamad |
author_facet | Adamus-Wlodarczyk, Agnieszka Wach, Radoslaw A. Ulanski, Piotr Rosiak, Janusz M. Socka, Marta Tsinas, Zois Al-Sheikhly, Mohamad |
author_sort | Adamus-Wlodarczyk, Agnieszka |
collection | PubMed |
description | This article demonstrates that ionizing radiation induces simultaneous crosslinking and scission in poly(trimethylene carbonate-co-d-lactide) diblock and random copolymers. Copolymer films were electron-beam (EB) irradiated up to 300 kGy under anaerobic conditions and subsequently examined by evaluation of their structure (FT-IR, NMR), molecular weight, intrinsic viscosities, and thermal properties. Radiation chemistry of the copolymers is strongly influenced by the content of ester linkages of the lactide component. At low lactide content, crosslinking reaction is the dominant one; however, as the lactide ratio increases, the ester linkages scission becomes more competent and exceeds the crosslinking. Electron paramagnetic resonance (EPR) measurements indicate that higher content of amorphous carbonate units in copolymers leads to a reduction in free radical yield and faster radical decay as compared to lactide-rich compositions. The domination of scission of ester bonds was confirmed by identifying the radiolytically produced alkoxyl and acetyl radicals, the latter being more stable due to its conjugated structure. |
format | Online Article Text |
id | pubmed-6404164 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-64041642019-04-02 On the Mechanisms of the Effects of Ionizing Radiation on Diblock and Random Copolymers of Poly(Lactic Acid) and Poly(Trimethylene Carbonate) Adamus-Wlodarczyk, Agnieszka Wach, Radoslaw A. Ulanski, Piotr Rosiak, Janusz M. Socka, Marta Tsinas, Zois Al-Sheikhly, Mohamad Polymers (Basel) Article This article demonstrates that ionizing radiation induces simultaneous crosslinking and scission in poly(trimethylene carbonate-co-d-lactide) diblock and random copolymers. Copolymer films were electron-beam (EB) irradiated up to 300 kGy under anaerobic conditions and subsequently examined by evaluation of their structure (FT-IR, NMR), molecular weight, intrinsic viscosities, and thermal properties. Radiation chemistry of the copolymers is strongly influenced by the content of ester linkages of the lactide component. At low lactide content, crosslinking reaction is the dominant one; however, as the lactide ratio increases, the ester linkages scission becomes more competent and exceeds the crosslinking. Electron paramagnetic resonance (EPR) measurements indicate that higher content of amorphous carbonate units in copolymers leads to a reduction in free radical yield and faster radical decay as compared to lactide-rich compositions. The domination of scission of ester bonds was confirmed by identifying the radiolytically produced alkoxyl and acetyl radicals, the latter being more stable due to its conjugated structure. MDPI 2018-06-16 /pmc/articles/PMC6404164/ /pubmed/30966706 http://dx.doi.org/10.3390/polym10060672 Text en © 2018 by the authors. 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 (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Adamus-Wlodarczyk, Agnieszka Wach, Radoslaw A. Ulanski, Piotr Rosiak, Janusz M. Socka, Marta Tsinas, Zois Al-Sheikhly, Mohamad On the Mechanisms of the Effects of Ionizing Radiation on Diblock and Random Copolymers of Poly(Lactic Acid) and Poly(Trimethylene Carbonate) |
title | On the Mechanisms of the Effects of Ionizing Radiation on Diblock and Random Copolymers of Poly(Lactic Acid) and Poly(Trimethylene Carbonate) |
title_full | On the Mechanisms of the Effects of Ionizing Radiation on Diblock and Random Copolymers of Poly(Lactic Acid) and Poly(Trimethylene Carbonate) |
title_fullStr | On the Mechanisms of the Effects of Ionizing Radiation on Diblock and Random Copolymers of Poly(Lactic Acid) and Poly(Trimethylene Carbonate) |
title_full_unstemmed | On the Mechanisms of the Effects of Ionizing Radiation on Diblock and Random Copolymers of Poly(Lactic Acid) and Poly(Trimethylene Carbonate) |
title_short | On the Mechanisms of the Effects of Ionizing Radiation on Diblock and Random Copolymers of Poly(Lactic Acid) and Poly(Trimethylene Carbonate) |
title_sort | on the mechanisms of the effects of ionizing radiation on diblock and random copolymers of poly(lactic acid) and poly(trimethylene carbonate) |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404164/ https://www.ncbi.nlm.nih.gov/pubmed/30966706 http://dx.doi.org/10.3390/polym10060672 |
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