Effect of electron beam irradiation on the properties of poly(tetramethylene oxide) and a poly(tetramethylene oxide)-based polyurethane
| Autor: | A. Rubio Hernández-Sampelayo, Ángel Marcos-Fernández, Esbaide Adem, Rodrigo Navarro |
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| Rok vydání: | 2020 |
| Předmět: |
Polyurethane
Materials science Chemical structure Radical Oxide Mechanical properties macromolecular substances Photochemistry 01 natural sciences 030218 nuclear medicine & medical imaging Ionizing radiation law.invention 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine law 0103 physical sciences Irradiation Crystallization chemistry.chemical_classification Radiation 010308 nuclear & particles physics Polymer Degradation mechanis chemistry Electron beam irradiation Poly(tetramethylene oxide) |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0969-806X |
| DOI: | 10.1016/j.radphyschem.2020.108905 |
| Popis: | Polyurethanes (PUs) based on poly(tetramethylene oxide) (PTMO) used in the biomedical sector can be exposed to ionizing radiation in vivo as implants during diagnosis (X-ray) or during radiotherapy treatment (gamma), or ex vivo for sterilization purposes (gamma, electron beam). This ionizing radiation can, at certain levels, cause degradation of the polymer. To understand the effect on those PUs, a high molecular weight PTMO (pTHF) and one PU based on PTMO (pTHF-MDI) were irradiated with electron beam and the changes in their chemical structure and physical properties with the dose were evaluated. Electron beam irradiation produced crosslinking and chain scission without significant predominance of one mechanism over the other in pTHF and predominance of crosslinking for pTHF-MDI. New saturated hydrocarbon species were detected in irradiated pTHF by proton NMR. These species were consistent with a mechanism where radicals were formed at alpha methylenes and chain scission took place at C–C bonds without significant oxidation, in disagreement with the mechanism proposed in literature. Crosslinking decreased significantly the crystallization and melting temperatures of pTHF and pTHF-MDI. Tensile properties of pTHF decreased rapidly with the increase in dose due to chain scission. The authors acknowledge the technical support provided by M. Vásquez and J. Galindo from Instituto de Física-UNAM in the irradiation of the samples with electrons. It is also acknowledged the donation of pTHF by Prof. Guzman and of polytetramethylene glycol 2000 by BASF. |
| Databáze: | OpenAIRE |
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