Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Significant loss of mechanical strength in archeological oak from the 17th century Vasa ship: correlation with cellulose degradation
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
Show others and affiliations
(English)Article in journal (Refereed) Submitted
Identifiers
URN: urn:nbn:se:kth:diva-32819OAI: oai:DiVA.org:kth-32819DiVA: diva2:412091
Note
QC 20110420Available from: 2011-04-20 Created: 2011-04-20 Last updated: 2011-11-09Bibliographically approved
In thesis
1. Effects of Cell Wall Structure on Tensile Properties of Hardwood: Effect of down-regulation of lignin on mechanical performance of transgenic hybrid aspen. Effect of chemical degradation on mechanical performance of archaeological oak from the Vasa ship.
Open this publication in new window or tab >>Effects of Cell Wall Structure on Tensile Properties of Hardwood: Effect of down-regulation of lignin on mechanical performance of transgenic hybrid aspen. Effect of chemical degradation on mechanical performance of archaeological oak from the Vasa ship.
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Wood is a complex material and the mechanical properties are influencedby a number of structural parameters. The objective of this study has been toinvestigate the relationship between the structure and the mechanical propertiesof hardwood. Two levels were of special interest, viz. the cellular structureand morphology of the wood, and the ultra-structure of the cell wall. In thenext step, it was of interest to examine how the mechanical properties ofhardwood change with spontaneous/induced changes in morphology and/orchemical composition beyond the natural variation found in nature.

Together, this constituted the framework and basis for two larger projects,one on European aspen (Populus tremula) and hybrid aspen (Populus tremulax Populus tremuloides), and one on European oak (Quercus robur). Amethodology was developed where the concept of relative density and compositemechanics rules served as two useful tools to assess the properties ofthe cell wall. Tensile testing in the longitudinal direction was combined withchemical examination of the material. This approach made it possible to revealthe mechanical role of the lignin in the cell wall of transgenic aspen trees,and investigate the consequences of holocellulose degradation in archaeologicaloak from the Vasa ship.

The study on transgenic aspen showed that a major reduction in lignin inPopulus leads to a small but significant reduction in the longitudinal stiffness.The longitudinal tensile strength was not reduced. The results are explainableby the fact that the load-bearing cellulose in the transgenic aspen retained itscrystallinity, aggregate size, microfibril angle, and absolute content per unitvolume. The results can contribute to the ongoing task of investigating andpinpointing the precise function of lignin in the cell wall of trees.

The mechanical property study on Vasa oak showed that the longitudinaltensile strength is severely reduced in several regions of the ship, andthat the reduction correlates with reduced average molecular weight of theholocellulose. This could not have been foreseen without a thorough mechanicaland chemical investigation, since the Vasa wood (with exception fromthe bacterially degraded surface regions) is morphologically intact and witha micro-structure comparable to that of recent oak. The results can be usedin the ongoing task of mapping the condition of the Vasa wood.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. viii, 67 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2011:14
Keyword
tensile strength, transgenic hybrid aspen, lignin down-regulation, the Vasa ship, chemical degradation, longitudinell draghållfasthet, transgen hybridasp, ligninnedreglering, Vasaskeppet, kemisk nedbrytning
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-32190 (URN)978-91-7415-914-1 (ISBN)
Public defence
2011-04-29, F3, Lindstedtsvägen 26, Stockholm, 13:00 (English)
Opponent
Supervisors
Note
QC 20110420Available from: 2011-04-20 Created: 2011-04-08 Last updated: 2011-04-26Bibliographically approved

Open Access in DiVA

No full text

Authority records BETA

Berglund, Lars

Search in DiVA

By author/editor
Bjurhager, IngelaBerglund, Lars
By organisation
Fibre and Polymer TechnologyBiocomposites

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 133 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf