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Basic factors influencing the strength loss in heat treatment processes for production of durable wood
2005 (English)Conference paper, Poster (Other academic)
Abstract [en]

Heat treatment of wood leads to improvement of properties such as durability and dimensional stability but also to loss in strength which can be an obstacle for use in wood products. The underlying explanation is often attributed to the degradation of hemicelluloses and lignin. In this work degradation by acid hydrolysis of cellulose is proposed to be a major cause for strength loss in heat treated wood. Hydrothermal treatment was performed at 180°C in a sealed autoclave where the wood samples were soaked in non-buffered and in buffered solutions at pH 4, 7 and 10. Also industrially produced samples of heat treated wood were analysed. The molecular chain length of cellulose was characterized by viscosimetric measurements of dissolved α-cellulose after mild delignification of the samples. The results clearly show that non-buffered systems similar to industrially heat treatment lead to a considerable degradation of cellulose. In the non-buffered systems the pH drops to approximately 3 (room temperature) as a result of heat treatment. Samples from industrially heat treated wood also show cellulose degradation to similar extent as the non-buffered samples. In buffered conditions at pH 7 and pH 10 the degradation of cellulose is clearly diminished. The results indicate that the cellulose degradation can be avoided by modifications that controls or minimizes the effect of acid hydrolysis during the heat treatment process

Place, publisher, year, edition, pages
2005.
Research subject
Wood Physics
Identifiers
URN: urn:nbn:se:ltu:diva-39146Local ID: dc74c3c0-0637-11dc-b09b-000ea68e967bOAI: oai:DiVA.org:ltu-39146DiVA: diva2:1012655
Conference
International Symposium on Wood, Fibre and Pulping Chemistry : 16/05/2005 - 19/05/2005
Note
Godkänd; 2005; Bibliografisk uppgift: Titel på proceedings: 59th Appita Annual Conference and Exhibition : incorporating the 13th ISWFPC Undertitel på proceedings: proceedings Sider: 417-419; 20070519 (ysko)Available from: 2016-10-03 Created: 2016-10-03Bibliographically approved

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Westermark, UllaSundqvist, Bror

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