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Natural Ageing of PLA Filaments, Can It Be Frozen?

The physical ageing of polylactic acid (PLA) is a phenomenon that changes the material’s properties over time. This ageing process is highly dependent on ambient variables, such as temperature and humidity. For PLA, the ageing is noticeable even at room temperatures, a process commonly referred to a...

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Autores principales: Orellana-Barrasa, Jaime, Ferrández-Montero, Ana, Ferrari, Begoña, Pastor, José Ygnacio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9416607/
https://www.ncbi.nlm.nih.gov/pubmed/36015618
http://dx.doi.org/10.3390/polym14163361
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author Orellana-Barrasa, Jaime
Ferrández-Montero, Ana
Ferrari, Begoña
Pastor, José Ygnacio
author_facet Orellana-Barrasa, Jaime
Ferrández-Montero, Ana
Ferrari, Begoña
Pastor, José Ygnacio
author_sort Orellana-Barrasa, Jaime
collection PubMed
description The physical ageing of polylactic acid (PLA) is a phenomenon that changes the material’s properties over time. This ageing process is highly dependent on ambient variables, such as temperature and humidity. For PLA, the ageing is noticeable even at room temperatures, a process commonly referred to as natural ageing. Stopping the ageing by freezing the material can be helpful to preserve the properties of the PLA and stabilise it at any time during its storage until it is required for testing. However, it is essential to demonstrate that the PLA’s mechanical properties are not degraded after defrosting the samples. Four different methods for stopping the ageing (anti-ageing processes) are analysed in this paper—all based on freezing and defrosting the PLA samples. We determine the temperature and ambient water vapor influence during the freezing and defrosting process using desiccant and zip bags. The material form selected is PLA filaments (no bulk material or scaffold structures) printed at 190 °C with diameters between 400 and 550 µm and frozen at −24 °C in the presence or absence of a desiccant. The impact of the anti-ageing processes on PLA’s ageing and mechanical integrity is studied regarding the thermal, mechanical and fractographical properties. In conclusion, an anti-ageing process is defined to successfully stop the natural ageing of the PLA for an indefinite length of time. This process does not affect the mechanical properties or the structural integrity of the PLA. As a result, large quantities of this material can be produced in a single batch and be safely stored to be later characterised under the same manufacturing and ageing conditions, which is currently a limiting factor from an experimental point of view as polymeric filament properties can show significant variety from batch to batch.
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spelling pubmed-94166072022-08-27 Natural Ageing of PLA Filaments, Can It Be Frozen? Orellana-Barrasa, Jaime Ferrández-Montero, Ana Ferrari, Begoña Pastor, José Ygnacio Polymers (Basel) Article The physical ageing of polylactic acid (PLA) is a phenomenon that changes the material’s properties over time. This ageing process is highly dependent on ambient variables, such as temperature and humidity. For PLA, the ageing is noticeable even at room temperatures, a process commonly referred to as natural ageing. Stopping the ageing by freezing the material can be helpful to preserve the properties of the PLA and stabilise it at any time during its storage until it is required for testing. However, it is essential to demonstrate that the PLA’s mechanical properties are not degraded after defrosting the samples. Four different methods for stopping the ageing (anti-ageing processes) are analysed in this paper—all based on freezing and defrosting the PLA samples. We determine the temperature and ambient water vapor influence during the freezing and defrosting process using desiccant and zip bags. The material form selected is PLA filaments (no bulk material or scaffold structures) printed at 190 °C with diameters between 400 and 550 µm and frozen at −24 °C in the presence or absence of a desiccant. The impact of the anti-ageing processes on PLA’s ageing and mechanical integrity is studied regarding the thermal, mechanical and fractographical properties. In conclusion, an anti-ageing process is defined to successfully stop the natural ageing of the PLA for an indefinite length of time. This process does not affect the mechanical properties or the structural integrity of the PLA. As a result, large quantities of this material can be produced in a single batch and be safely stored to be later characterised under the same manufacturing and ageing conditions, which is currently a limiting factor from an experimental point of view as polymeric filament properties can show significant variety from batch to batch. MDPI 2022-08-17 /pmc/articles/PMC9416607/ /pubmed/36015618 http://dx.doi.org/10.3390/polym14163361 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
Orellana-Barrasa, Jaime
Ferrández-Montero, Ana
Ferrari, Begoña
Pastor, José Ygnacio
Natural Ageing of PLA Filaments, Can It Be Frozen?
title Natural Ageing of PLA Filaments, Can It Be Frozen?
title_full Natural Ageing of PLA Filaments, Can It Be Frozen?
title_fullStr Natural Ageing of PLA Filaments, Can It Be Frozen?
title_full_unstemmed Natural Ageing of PLA Filaments, Can It Be Frozen?
title_short Natural Ageing of PLA Filaments, Can It Be Frozen?
title_sort natural ageing of pla filaments, can it be frozen?
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9416607/
https://www.ncbi.nlm.nih.gov/pubmed/36015618
http://dx.doi.org/10.3390/polym14163361
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