Variation of Nanostructures, Molecular Interactions, and Anisotropic Elastic Moduli of Lignocellulosic Cell Walls with Moisture

Abstract A combination of experimental, theoretical and numerical studies is used to investigate the variation of elastic moduli of lignocellulosic (bamboo) fiber cell walls with moisture content (MC). Our Nanoindentation results show that the longitudinal elastic modulus initially increased to a ma...

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Autores principales:	S. Youssefian, J. E. Jakes, N. Rahbar
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/c1fbc6ef61344222a6d0d2e03bf2b1e9
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spelling	oai:doaj.org-article:c1fbc6ef61344222a6d0d2e03bf2b1e92021-12-02T16:06:00ZVariation of Nanostructures, Molecular Interactions, and Anisotropic Elastic Moduli of Lignocellulosic Cell Walls with Moisture10.1038/s41598-017-02288-w2045-2322https://doaj.org/article/c1fbc6ef61344222a6d0d2e03bf2b1e92017-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-02288-whttps://doaj.org/toc/2045-2322Abstract A combination of experimental, theoretical and numerical studies is used to investigate the variation of elastic moduli of lignocellulosic (bamboo) fiber cell walls with moisture content (MC). Our Nanoindentation results show that the longitudinal elastic modulus initially increased to a maximum value at about 3% MC and then decreased linearly with increasing MC. In contrast, the transverse moduli decrease linearly with MC. We showed that amorphous materials in cell walls have key roles in the variation of elastic modulus with increasing MC. Elastic modulus of lignin, calculated by molecular dynamics simulations, increases initially with increasing MC, and then decreases. In contrast, elastic modulus of hemicellulose decreases constantly with MC. Below 10% MC, water molecules tend to break hydrogen bonds between polymer chains and form new hydrogen bond bridges between the polymer chains, while above 10% MC, water molecules aggregate together and create nano-droplets inside the materials. During the process of bridging, the fractional free volume of lignin decreases. The free volume reduction along with formation of hydrogen bond bridges causes a growth in elastic modulus of lignin at low MC. The constant increase of hemicellulose free volume, however, causes the aggregation of voids in the system and diminution of elastic properties.S. YoussefianJ. E. JakesN. RahbarNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-10 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q S. Youssefian J. E. Jakes N. Rahbar Variation of Nanostructures, Molecular Interactions, and Anisotropic Elastic Moduli of Lignocellulosic Cell Walls with Moisture
description	Abstract A combination of experimental, theoretical and numerical studies is used to investigate the variation of elastic moduli of lignocellulosic (bamboo) fiber cell walls with moisture content (MC). Our Nanoindentation results show that the longitudinal elastic modulus initially increased to a maximum value at about 3% MC and then decreased linearly with increasing MC. In contrast, the transverse moduli decrease linearly with MC. We showed that amorphous materials in cell walls have key roles in the variation of elastic modulus with increasing MC. Elastic modulus of lignin, calculated by molecular dynamics simulations, increases initially with increasing MC, and then decreases. In contrast, elastic modulus of hemicellulose decreases constantly with MC. Below 10% MC, water molecules tend to break hydrogen bonds between polymer chains and form new hydrogen bond bridges between the polymer chains, while above 10% MC, water molecules aggregate together and create nano-droplets inside the materials. During the process of bridging, the fractional free volume of lignin decreases. The free volume reduction along with formation of hydrogen bond bridges causes a growth in elastic modulus of lignin at low MC. The constant increase of hemicellulose free volume, however, causes the aggregation of voids in the system and diminution of elastic properties.
format	article
author	S. Youssefian J. E. Jakes N. Rahbar
author_facet	S. Youssefian J. E. Jakes N. Rahbar
author_sort	S. Youssefian
title	Variation of Nanostructures, Molecular Interactions, and Anisotropic Elastic Moduli of Lignocellulosic Cell Walls with Moisture
title_short	Variation of Nanostructures, Molecular Interactions, and Anisotropic Elastic Moduli of Lignocellulosic Cell Walls with Moisture
title_full	Variation of Nanostructures, Molecular Interactions, and Anisotropic Elastic Moduli of Lignocellulosic Cell Walls with Moisture
title_fullStr	Variation of Nanostructures, Molecular Interactions, and Anisotropic Elastic Moduli of Lignocellulosic Cell Walls with Moisture
title_full_unstemmed	Variation of Nanostructures, Molecular Interactions, and Anisotropic Elastic Moduli of Lignocellulosic Cell Walls with Moisture
title_sort	variation of nanostructures, molecular interactions, and anisotropic elastic moduli of lignocellulosic cell walls with moisture
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/c1fbc6ef61344222a6d0d2e03bf2b1e9
work_keys_str_mv	AT syoussefian variationofnanostructuresmolecularinteractionsandanisotropicelasticmodulioflignocellulosiccellwallswithmoisture AT jejakes variationofnanostructuresmolecularinteractionsandanisotropicelasticmodulioflignocellulosiccellwallswithmoisture AT nrahbar variationofnanostructuresmolecularinteractionsandanisotropicelasticmodulioflignocellulosiccellwallswithmoisture
_version_	1718385173636055040

Variation of Nanostructures, Molecular Interactions, and Anisotropic Elastic Moduli of Lignocellulosic Cell Walls with Moisture

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