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Deterioration of recent oak by iron compound

a comparison with Vasa oak

Johansson, Charles Shahin (2012). Deterioration of recent oak by iron compound. Uppsala : Sveriges lantbruksuniv.
ISBN 978-91-576-9075-3
[Licentiate thesis]

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Abstract

Wood degradation in the historical warship Vasa has been studied systematically regarding the chemical and physical properties. The presence of iron(II) seems to be one important factor for the degradation of the wood, causing reduction of its tensile strength. This is unfortunately a serious problem as iron(II) compounds are abundant in Vasa wood. However, it is a question whether the deterioration reactions still go on or if they have stopped soon after the ship was salvaged. The aim of this study is to investigate the possible chemical reasons for the deterioration of the wood. This has been accomplished by use of model experiments with recent oak. Series of recent oak wood, cut in a “dog bone shape”, were placed in aqueous solutions containing 0.1 M iron(II) chloride. These samples were exposed to different concentrations of oxygen for one week, one month and one year. By use of an Instron universal testing machine the samples were pulled apart and the tensile strength required to break the wood registered. Samples exposed to iron(II) and oxygen showed a significant decrease in tensile strength. Variation of time and oxygen exposure showed that the rate of decrease in tensile strength is more intense at the initial stages of the exposure. The results also showed that exposure to pure oxygen, increased the deterioration rate. Oxygen treated samples showed an increase in the formation of low-molecular organic acids in the wood tissue and pH decreased to approximately 2 to 3. The chemical properties of holocellulose in recent oak treated with aqueous iron(II) solutions in the presence of oxygen conforms very well with degraded wood from the Vasa. The deterioration process in the Vasa wood seems to be limited in time and probably took place soon after oxygen exposure. The abundance of iron(II) compounds in Vasa wood and accessibility of oxygen and water will determine the level of deterioration of the wood.

Authors/Creators:Johansson, Charles Shahin
Title:Deterioration of recent oak by iron compound
Subtitle:a comparison with Vasa oak
Year of publishing :May 2012
Number of Pages:52
Papers/manuscripts:
NumberReferences
I.Johansson, C; Bjurhager, I and Almkvist, G. A study on the mechanical properties and degradation of oak wood. Effects of iron(II) and oxygen on the mechanical strength in the longitudinal direction. (Manuscript)
II.Johansson, C; Bjurhager, I and Almkvist, G. A study on the mechanical properties and degradation of oak wood. Oxygen consumption related to iron initiated degradation of recent oak wood. (Manuscript)
Place of Publication:Uppsala
Publisher:Institutionen för kemi, Sveriges lantbruksuniversitet
ISBN for printed version:978-91-576-9075-3
Language:English
Publication Type:Licentiate thesis
Full Text Status:Public
Agris subject categories.:X Agricola extesions > X50 Chemistry
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 104 Chemical Sciences > Inorganic Chemistry
(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 203 Mechanical Engineering > Applied Mechanics
(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 204 Chemical Engineering > Corrosion Engineering
Agrovoc terms:wood, chemical degradation, wood decay, iron, oxalic acid, tensile strength, quercus
Keywords:The historical warship Vasa, oak wood, tensile strength, iron, oxalic acid, acid hydrolysis, oxidative degradation
URN:NBN:urn:nbn:se:slu:epsilon-e-485
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-485
ID Code:8864
Department:(NL, NJ) > Dept. of Chemistry (until 131231)
Deposited By: Charles Shahin Johansson
Deposited On:11 May 2012 07:47
Metadata Last Modified:02 Dec 2014 10:50

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