Marie Hartwig-Nair, Alexandr Nasedkin, Klara Hackenstrass, Emiliano De Santis, Sara Florisson, Malin Wohlert
{"title":"Lignin hygroexpansion in compression and opposite wood - a molecular dynamics study","authors":"Marie Hartwig-Nair, Alexandr Nasedkin, Klara Hackenstrass, Emiliano De Santis, Sara Florisson, Malin Wohlert","doi":"10.1007/s00226-024-01624-4","DOIUrl":null,"url":null,"abstract":"<div><p>Softwood branches develop compression wood (CW) in the lower parts of the branch, while opposite wood (OW) develops on the upper. These wood types differ in structure at several length scales, among others in the chemical composition of their lignin matrix. While OW mostly contains guaiacyl (G) units, CW is known to contain a substantial fraction of 4-hydroxyphenyl (H) lignin. In this study, the impact this difference has on lignin hygroexpansion and interaction with water is studied by the means of atomistic models and molecular dynamics computer simulations of lignin systems at different levels of hydration. It was found that, despite the minor difference in chemical composition, there are differences in swelling, structure and water dynamics. CW lignin is found to have a higher uniaxial swelling coefficient, since the phase separation between lignin and water is more pronounced. This behavior is linked to structural differences, where intermolecular <span>\\({\\pi -\\pi }\\)</span> stacking is more common in CW lignin and hydrogen bonding to water more pronounced in OW lignin. These findings are of interest for understanding the role of lignin in CW, and general understanding of moisture interaction with lignin inside wood cell walls.</p></div>","PeriodicalId":810,"journal":{"name":"Wood Science and Technology","volume":"59 1","pages":""},"PeriodicalIF":3.1000,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00226-024-01624-4.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Wood Science and Technology","FirstCategoryId":"88","ListUrlMain":"https://link.springer.com/article/10.1007/s00226-024-01624-4","RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"FORESTRY","Score":null,"Total":0}
引用次数: 0
Abstract
Softwood branches develop compression wood (CW) in the lower parts of the branch, while opposite wood (OW) develops on the upper. These wood types differ in structure at several length scales, among others in the chemical composition of their lignin matrix. While OW mostly contains guaiacyl (G) units, CW is known to contain a substantial fraction of 4-hydroxyphenyl (H) lignin. In this study, the impact this difference has on lignin hygroexpansion and interaction with water is studied by the means of atomistic models and molecular dynamics computer simulations of lignin systems at different levels of hydration. It was found that, despite the minor difference in chemical composition, there are differences in swelling, structure and water dynamics. CW lignin is found to have a higher uniaxial swelling coefficient, since the phase separation between lignin and water is more pronounced. This behavior is linked to structural differences, where intermolecular \({\pi -\pi }\) stacking is more common in CW lignin and hydrogen bonding to water more pronounced in OW lignin. These findings are of interest for understanding the role of lignin in CW, and general understanding of moisture interaction with lignin inside wood cell walls.
期刊介绍:
Wood Science and Technology publishes original scientific research results and review papers covering the entire field of wood material science, wood components and wood based products. Subjects are wood biology and wood quality, wood physics and physical technologies, wood chemistry and chemical technologies. Latest advances in areas such as cell wall and wood formation; structural and chemical composition of wood and wood composites and their property relations; physical, mechanical and chemical characterization and relevant methodological developments, and microbiological degradation of wood and wood based products are reported. Topics related to wood technology include machining, gluing, and finishing, composite technology, wood modification, wood mechanics, creep and rheology, and the conversion of wood into pulp and biorefinery products.