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Analysis of the Effect of Processing Conditions on Physical Properties of Thermally Set Cellulose Hydrogels

Cellulose-based hydrogels were prepared by dissolving cellulose in aqueous sodium hydroxide (NaOH)/urea solutions and casting it into complex shapes by the use of sacrificial templates followed by thermal gelation of the solution. Both the gelling temperatures used (40–80 °C), as well as the method...

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Autores principales: Huber, Tim, Feast, Sean, Dimartino, Simone, Cen, Wanwen, Fee, Conan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6479291/
https://www.ncbi.nlm.nih.gov/pubmed/30939751
http://dx.doi.org/10.3390/ma12071066
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author Huber, Tim
Feast, Sean
Dimartino, Simone
Cen, Wanwen
Fee, Conan
author_facet Huber, Tim
Feast, Sean
Dimartino, Simone
Cen, Wanwen
Fee, Conan
author_sort Huber, Tim
collection PubMed
description Cellulose-based hydrogels were prepared by dissolving cellulose in aqueous sodium hydroxide (NaOH)/urea solutions and casting it into complex shapes by the use of sacrificial templates followed by thermal gelation of the solution. Both the gelling temperatures used (40–80 °C), as well as the method of heating by either induction in the form of a water bath and hot press or radiation by microwaves could be shown to have a significant effect on the compressive strength and modulus of the prepared hydrogels. Lower gelling temperatures and shorter heating times were found to result in stronger and stiffer gels. Both the effect of physical cross-linking via the introduction of additional non-dissolving cellulosic material, as well as chemical cross-linking by the introduction of epichlorohydrin (ECH), and a combination of both applied during the gelation process could be shown to affect both the mechanical properties and microstructure of the hydrogels. The added cellulose acts as a physical-cross-linking agent strengthening the hydrogen-bond network as well as a reinforcing phase improving the mechanical properties. However, chemical cross-linking of an unreinforced gel leads to unfavourable bonding and cellulose network formation, resulting in drastically increased pore sizes and reduced mechanical properties. In both cases, chemical cross-linking leads to larger internal pores.
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spelling pubmed-64792912019-04-29 Analysis of the Effect of Processing Conditions on Physical Properties of Thermally Set Cellulose Hydrogels Huber, Tim Feast, Sean Dimartino, Simone Cen, Wanwen Fee, Conan Materials (Basel) Article Cellulose-based hydrogels were prepared by dissolving cellulose in aqueous sodium hydroxide (NaOH)/urea solutions and casting it into complex shapes by the use of sacrificial templates followed by thermal gelation of the solution. Both the gelling temperatures used (40–80 °C), as well as the method of heating by either induction in the form of a water bath and hot press or radiation by microwaves could be shown to have a significant effect on the compressive strength and modulus of the prepared hydrogels. Lower gelling temperatures and shorter heating times were found to result in stronger and stiffer gels. Both the effect of physical cross-linking via the introduction of additional non-dissolving cellulosic material, as well as chemical cross-linking by the introduction of epichlorohydrin (ECH), and a combination of both applied during the gelation process could be shown to affect both the mechanical properties and microstructure of the hydrogels. The added cellulose acts as a physical-cross-linking agent strengthening the hydrogen-bond network as well as a reinforcing phase improving the mechanical properties. However, chemical cross-linking of an unreinforced gel leads to unfavourable bonding and cellulose network formation, resulting in drastically increased pore sizes and reduced mechanical properties. In both cases, chemical cross-linking leads to larger internal pores. MDPI 2019-04-01 /pmc/articles/PMC6479291/ /pubmed/30939751 http://dx.doi.org/10.3390/ma12071066 Text en © 2019 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
Huber, Tim
Feast, Sean
Dimartino, Simone
Cen, Wanwen
Fee, Conan
Analysis of the Effect of Processing Conditions on Physical Properties of Thermally Set Cellulose Hydrogels
title Analysis of the Effect of Processing Conditions on Physical Properties of Thermally Set Cellulose Hydrogels
title_full Analysis of the Effect of Processing Conditions on Physical Properties of Thermally Set Cellulose Hydrogels
title_fullStr Analysis of the Effect of Processing Conditions on Physical Properties of Thermally Set Cellulose Hydrogels
title_full_unstemmed Analysis of the Effect of Processing Conditions on Physical Properties of Thermally Set Cellulose Hydrogels
title_short Analysis of the Effect of Processing Conditions on Physical Properties of Thermally Set Cellulose Hydrogels
title_sort analysis of the effect of processing conditions on physical properties of thermally set cellulose hydrogels
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6479291/
https://www.ncbi.nlm.nih.gov/pubmed/30939751
http://dx.doi.org/10.3390/ma12071066
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